| blob | 86691d9e9a5a8c96de6bb745177499ca7986991b |
1 ------------------------------------------------------------------------------
2 -- --
3 -- GNAT COMPILER COMPONENTS --
4 -- --
5 -- S E M _ R E S --
6 -- --
7 -- B o d y --
8 -- --
9 -- Copyright (C) 1992-2016, Free Software Foundation, Inc. --
10 -- --
11 -- GNAT is free software; you can redistribute it and/or modify it under --
12 -- terms of the GNU General Public License as published by the Free Soft- --
13 -- ware Foundation; either version 3, or (at your option) any later ver- --
14 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
15 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
16 -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
17 -- for more details. You should have received a copy of the GNU General --
18 -- Public License distributed with GNAT; see file COPYING3. If not, go to --
19 -- http://www.gnu.org/licenses for a complete copy of the license. --
20 -- --
21 -- GNAT was originally developed by the GNAT team at New York University. --
22 -- Extensive contributions were provided by Ada Core Technologies Inc. --
23 -- --
24 ------------------------------------------------------------------------------
87 -----------------------
88 -- Local Subprograms --
89 -----------------------
91 -- Second pass (top-down) type checking and overload resolution procedures
92 -- Typ is the type required by context. These procedures propagate the
93 -- type information recursively to the descendants of N. If the node is not
94 -- overloaded, its Etype is established in the first pass. If overloaded,
95 -- the Resolve routines set the correct type. For arithmetic operators, the
96 -- Etype is the base type of the context.
98 -- Note that Resolve_Attribute is separated off in Sem_Attr
101 -- Enforce the restrictions on the use of discriminants when constraining
102 -- a component of a discriminated type (record or concurrent type).
105 -- Given a node for an operator associated with type T, check that the
106 -- operator is visible. Operators all of whose operands are universal must
107 -- be checked for visibility during resolution because their type is not
108 -- determinable based on their operands.
110 procedure Check_Fully_Declared_Prefix
113 -- Check that the type of the prefix of a dereference is not incomplete
116 -- Given a call node, N, which is known to occur immediately within the
117 -- subprogram being called, determines whether it is a detectable case of
118 -- an infinite recursion, and if so, outputs appropriate messages. Returns
119 -- True if an infinite recursion is detected, and False otherwise.
122 -- If the type of the object being initialized uses the secondary stack
123 -- directly or indirectly, create a transient scope for the call to the
124 -- init proc. This is because we do not create transient scopes for the
125 -- initialization of individual components within the init proc itself.
126 -- Could be optimized away perhaps?
129 -- N is the node for a logical operator. If the operator is predefined, and
130 -- the root type of the operands is Standard.Boolean, then a check is made
131 -- for restriction No_Direct_Boolean_Operators. This procedure also handles
132 -- the style check for Style_Check_Boolean_And_Or.
135 -- N is either an indexed component or a selected component. This function
136 -- returns true if the prefix refers to an object that has an address
137 -- clause (the case in which we may want to issue a warning).
140 -- Determine whether E is an access type declared by an access declaration,
141 -- and not an (anonymous) allocator type.
144 -- Utility to check whether the entity for an operator is a predefined
145 -- operator, in which case the expression is left as an operator in the
146 -- tree (else it is rewritten into a call). An instance of an intrinsic
147 -- conversion operation may be given an operator name, but is not treated
148 -- like an operator. Note that an operator that is an imported back-end
149 -- builtin has convention Intrinsic, but is expected to be rewritten into
150 -- a call, so such an operator is not treated as predefined by this
151 -- predicate.
154 -- If a default expression in entry call N depends on the discriminants
155 -- of the task, it must be replaced with a reference to the discriminant
156 -- of the task being called.
158 procedure Resolve_Op_Concat_Arg
163 -- Internal procedure for Resolve_Op_Concat to resolve one operand of
164 -- concatenation operator. The operand is either of the array type or of
165 -- the component type. If the operand is an aggregate, and the component
166 -- type is composite, this is ambiguous if component type has aggregates.
169 -- Does the first part of the work of Resolve_Op_Concat
172 -- Does the "rest" of the work of Resolve_Op_Concat, after the left operand
173 -- has been resolved. See Resolve_Op_Concat for details.
211 function Operator_Kind
214 -- Utility to map the name of an operator into the corresponding Node. Used
215 -- by other node rewriting procedures.
218 -- Resolve actuals of call, and add default expressions for missing ones.
219 -- N is the Node_Id for the subprogram call, and Nam is the entity of the
220 -- called subprogram.
223 -- Called from Resolve_Call, when the prefix denotes an entry or element
224 -- of entry family. Actuals are resolved as for subprograms, and the node
225 -- is rebuilt as an entry call. Also called for protected operations. Typ
226 -- is the context type, which is used when the operation is a protected
227 -- function with no arguments, and the return value is indexed.
230 -- A call to a user-defined intrinsic operator is rewritten as a call to
231 -- the corresponding predefined operator, with suitable conversions. Note
232 -- that this applies only for intrinsic operators that denote predefined
233 -- operators, not ones that are intrinsic imports of back-end builtins.
236 -- Ditto, for arithmetic unary operators
239 -- If an operator node resolves to a call to a user-defined operator,
240 -- rewrite the node as a function call.
242 procedure Make_Call_Into_Operator
246 -- Inverse transformation: if an operator is given in functional notation,
247 -- then after resolving the node, transform into an operator node, so that
248 -- operands are resolved properly. Recall that predefined operators do not
249 -- have a full signature and special resolution rules apply.
251 procedure Rewrite_Renamed_Operator
255 -- An operator can rename another, e.g. in an instantiation. In that
256 -- case, the proper operator node must be constructed and resolved.
259 -- The String_Literal_Subtype is built for all strings that are not
260 -- operands of a static concatenation operation. If the argument is not
261 -- a N_String_Literal node, then the call has no effect.
264 -- Build subtype of array type, with the range specified by the slice
267 -- Called after N has been resolved and evaluated, but before range checks
268 -- have been applied. Currently simplifies a combination of floating-point
269 -- to integer conversion and Rounding or Truncation attribute.
272 -- A universal_fixed expression in an universal context is unambiguous if
273 -- there is only one applicable fixed point type. Determining whether there
274 -- is only one requires a search over all visible entities, and happens
275 -- only in very pathological cases (see 6115-006).
277 -------------------------
278 -- Ambiguous_Character --
279 -------------------------
284 begin
288 -- First the ones in Standard
293 -- Include Wide_Wide_Character in Ada 2005 mode
299 -- Now any other types that match
309 -------------------------
310 -- Analyze_And_Resolve --
311 -------------------------
314 begin
320 begin
325 -- Versions with check(s) suppressed
327 procedure Analyze_And_Resolve
331 is
334 begin
336 declare
338 begin
344 else
345 declare
347 begin
355 and then Scope_Is_Transient
356 then
357 -- This can only happen if a transient scope was created for an inner
358 -- expression, which will be removed upon completion of the analysis
359 -- of an enclosing construct. The transient scope must have the
360 -- suppress status of the enclosing environment, not of this Analyze
361 -- call.
364 Scope_Suppress;
368 procedure Analyze_And_Resolve
371 is
374 begin
376 declare
378 begin
384 else
385 declare
387 begin
396 Scope_Suppress;
400 ----------------------------
401 -- Check_Discriminant_Use --
402 ----------------------------
410 begin
411 -- Any use in a spec-expression is legal
418 -- Discriminant cannot be used to constrain a scalar type
425 then
430 -- The following check catches the unusual case where a
431 -- discriminant appears within an index constraint that is part
432 -- of a larger expression within a constraint on a component,
433 -- e.g. "C : Int range 1 .. F (new A(1 .. D))". For now we only
434 -- check case of record components, and note that a similar check
435 -- should also apply in the case of discriminant constraints
436 -- below. ???
438 -- Note that the check for N_Subtype_Declaration below is to
439 -- detect the valid use of discriminants in the constraints of a
440 -- subtype declaration when this subtype declaration appears
441 -- inside the scope of a record type (which is syntactically
442 -- illegal, but which may be created as part of derived type
443 -- processing for records). See Sem_Ch3.Build_Derived_Record_Type
444 -- for more info.
448 and then not
450 and then
452 N_Subtype_Declaration)
454 then
455 Error_Msg_N
460 -- Detect a common error:
462 -- type R (D : Positive := 100) is record
463 -- Name : String (1 .. D);
464 -- end record;
466 -- The default value causes an object of type R to be allocated
467 -- with room for Positive'Last characters. The RM does not mandate
468 -- the allocation of the maximum size, but that is what GNAT does
469 -- so we should warn the programmer that there is a problem.
478 -- Return True if type T has a large enough range that any
479 -- array whose index type covered the whole range of the type
480 -- would likely raise Storage_Error.
482 ------------------------
483 -- Large_Storage_Type --
484 ------------------------
487 begin
488 -- The type is considered large if its bounds are known at
489 -- compile time and if it requires at least as many bits as
490 -- a Positive to store the possible values.
494 and then
499 -- Start of processing for Check_Large
501 begin
502 -- Check that the Disc has a large range
508 -- If the enclosing type is limited, we allocate only the
509 -- default value, not the maximum, and there is no need for
510 -- a warning.
516 -- Check that it is the high bound
520 then
524 -- Check the array allows a large range at this bound. First
525 -- find the array
539 -- Next, find the dimension
547 loop
556 -- Now, check the dimension has a large range
562 -- Warn about the danger
564 Error_Msg_N
574 -- Legal case is in index or discriminant constraint
577 N_Discriminant_Association)
578 then
580 Error_Msg_N
585 then
586 Error_Msg_N
592 -- Otherwise, context is an expression. It should not be within (i.e. a
593 -- subexpression of) a constraint for a component.
595 else
599 N_Subtype_Indication,
600 N_Entry_Declaration)
601 loop
607 -- If the discriminant is used in an expression that is a bound of a
608 -- scalar type, an Itype is created and the bounds are attached to
609 -- its range, not to the original subtype indication. Such use is of
610 -- course a double fault.
614 N_Derived_Type_Definition)
617 -- The constraint itself may be given by a subtype indication,
618 -- rather than by a more common discrete range.
621 and then
625 then
626 Error_Msg_N
632 --------------------------------
633 -- Check_For_Visible_Operator --
634 --------------------------------
637 begin
639 Error_Msg_NE -- CODEFIX
641 Error_Msg_N -- CODEFIX
646 ----------------------------------
647 -- Check_Fully_Declared_Prefix --
648 ----------------------------------
650 procedure Check_Fully_Declared_Prefix
653 is
654 begin
655 -- Check that the designated type of the prefix of a dereference is
656 -- not an incomplete type. This cannot be done unconditionally, because
657 -- dereferences of private types are legal in default expressions. This
658 -- case is taken care of in Check_Fully_Declared, called below. There
659 -- are also 2005 cases where it is legal for the prefix to be unfrozen.
661 -- This consideration also applies to similar checks for allocators,
662 -- qualified expressions, and type conversions.
664 -- An additional exception concerns other per-object expressions that
665 -- are not directly related to component declarations, in particular
666 -- representation pragmas for tasks. These will be per-object
667 -- expressions if they depend on discriminants or some global entity.
668 -- If the task has access discriminants, the designated type may be
669 -- incomplete at the point the expression is resolved. This resolution
670 -- takes place within the body of the initialization procedure, where
671 -- the discriminant is replaced by its discriminal.
675 then
678 -- Ada 2005 (AI-326): Tagged incomplete types allowed. The wrong usages
679 -- are handled by Analyze_Access_Attribute, Analyze_Assignment,
680 -- Analyze_Object_Renaming, and Freeze_Entity.
686 E_Incomplete_Type
688 then
690 else
695 ------------------------------
696 -- Check_Infinite_Recursion --
697 ------------------------------
704 -- Check whether list of actuals is identical to list of formals of
705 -- called function (which is also the enclosing scope).
707 ------------------------
708 -- Same_Argument_List --
709 ------------------------
716 begin
719 else
737 -- Start of processing for Check_Infinite_Recursion
739 begin
740 -- Special case, if this is a procedure call and is a call to the
741 -- current procedure with the same argument list, then this is for
742 -- sure an infinite recursion and we insert a call to raise SE.
746 and then Same_Argument_List
747 then
748 declare
750 begin
754 then
766 -- If not that special case, search up tree, quitting if we reach a
767 -- construct (e.g. a conditional) that tells us that this is not a
768 -- case for an infinite recursion warning.
771 loop
774 -- If no parent, then we were not inside a subprogram, this can for
775 -- example happen when processing certain pragmas in a spec. Just
776 -- return False in this case.
782 -- Done if we get to subprogram body, this is definitely an infinite
783 -- recursion case if we did not find anything to stop us.
787 -- If appearing in conditional, result is false
790 N_And_Then,
791 N_Case_Expression,
792 N_Case_Statement,
793 N_If_Expression,
794 N_If_Statement)
795 then
800 then
801 -- If the call is the expression of a return statement and the
802 -- actuals are identical to the formals, it's worth a warning.
803 -- However, we skip this if there is an immediately preceding
804 -- raise statement, since the call is never executed.
806 -- Furthermore, this corresponds to a common idiom:
808 -- function F (L : Thing) return Boolean is
809 -- begin
810 -- raise Program_Error;
811 -- return F (L);
812 -- end F;
814 -- for generating a stub function
817 and then Same_Argument_List
818 then
821 -- OK, return statement is in a statement list, look for raise
823 declare
826 begin
827 -- Skip past N_Freeze_Entity nodes generated by expansion
832 loop
836 -- If no raise statement, give warning. We look at the
837 -- original node, because in the case of "raise ... with
838 -- ...", the node has been transformed into a call.
841 and then
849 else
861 -------------------------------
862 -- Check_Initialization_Call --
863 -------------------------------
869 -- Check whether the creation of an object of the type will involve
870 -- use of the secondary stack. If T is a record type, this is true
871 -- if the expression for some component uses the secondary stack, e.g.
872 -- through a call to a function that returns an unconstrained value.
873 -- False if T is controlled, because cleanups occur elsewhere.
875 -------------
876 -- Uses_SS --
877 -------------
884 begin
885 -- Normally we want to use the underlying type, but if it's not set
886 -- then continue with T.
903 then
904 -- The expression for a dynamic component may be rewritten
905 -- as a dereference, so retrieve original node.
909 -- Return True if the expression is a call to a function
910 -- (including an attribute function such as Image, or a
911 -- user-defined operator) with a result that requires a
912 -- transient scope.
919 then
932 else
937 -- Start of processing for Check_Initialization_Call
939 begin
940 -- Establish a transient scope if the type needs it
947 ---------------------------------------
948 -- Check_No_Direct_Boolean_Operators --
949 ---------------------------------------
952 begin
955 then
956 -- Restriction only applies to original source code
963 -- Do style check (but skip if in instance, error is on template)
972 ------------------------------
973 -- Check_Parameterless_Call --
974 ------------------------------
980 -- If the prefix is of an access_to_subprogram type, the node must be
981 -- rewritten as a call. Ditto if the prefix is overloaded and all its
982 -- interpretations are access to subprograms.
984 ---------------------------
985 -- Prefix_Is_Access_Subp --
986 ---------------------------
992 begin
993 -- If the context is an attribute reference that can apply to
994 -- functions, this is never a parameterless call (RM 4.1.4(6)).
998 Name_Code_Address,
999 Name_Access)
1000 then
1005 return
1008 else
1013 then
1024 -- Start of processing for Check_Parameterless_Call
1026 begin
1027 -- Defend against junk stuff if errors already detected
1034 then
1041 -- If the context expects a value, and the name is a procedure, this is
1042 -- most likely a missing 'Access. Don't try to resolve the parameterless
1043 -- call, error will be caught when the outer call is analyzed.
1048 and then
1050 N_Function_Call,
1051 N_Procedure_Call_Statement)
1052 then
1056 -- Rewrite as call if overloadable entity that is (or could be, in the
1057 -- overloaded case) a function call. If we know for sure that the entity
1058 -- is an enumeration literal, we do not rewrite it.
1060 -- If the entity is the name of an operator, it cannot be a call because
1061 -- operators cannot have default parameters. In this case, this must be
1062 -- a string whose contents coincide with an operator name. Set the kind
1063 -- of the node appropriately.
1071 -- Rewrite as call if it is an explicit dereference of an expression of
1072 -- a subprogram access type, and the subprogram type is not that of a
1073 -- procedure or entry.
1075 or else
1078 -- Rewrite as call if it is a selected component which is a function,
1079 -- this is the case of a call to a protected function (which may be
1080 -- overloaded with other protected operations).
1082 or else
1085 or else
1087 E_Procedure)
1090 -- If one of the above three conditions is met, rewrite as call. Apply
1091 -- the rewriting only once.
1093 then
1096 then
1098 -- This may be a prefixed call that was not fully analyzed, e.g.
1099 -- an actual in an instance.
1104 then
1112 -- The node is the name of the parameterless call. Preserve its
1113 -- descendants, which may be complex expressions.
1117 -- If overloaded, overload set belongs to new copy
1121 -- Change node to parameterless function call (note that the
1122 -- Parameter_Associations associations field is left set to Empty,
1123 -- its normal default value since there are no parameters)
1141 --------------------------------
1142 -- Is_Atomic_Ref_With_Address --
1143 --------------------------------
1148 begin
1152 else
1153 declare
1156 begin
1164 -----------------------------
1165 -- Is_Definite_Access_Type --
1166 -----------------------------
1170 begin
1176 ----------------------
1177 -- Is_Predefined_Op --
1178 ----------------------
1181 begin
1182 -- Predefined operators are intrinsic subprograms
1188 -- A call to a back-end builtin is never a predefined operator
1199 -----------------------------
1200 -- Make_Call_Into_Operator --
1201 -----------------------------
1203 procedure Make_Call_Into_Operator
1207 is
1222 -- If the operand is not universal, and the operator is given by an
1223 -- expanded name, verify that the operand has an interpretation with a
1224 -- type defined in the given scope of the operator.
1227 -- Find a type of the given class in package Pack that contains the
1228 -- operator.
1230 ---------------------------
1231 -- Operand_Type_In_Scope --
1232 ---------------------------
1239 begin
1243 else
1257 ---------------
1258 -- Type_In_P --
1259 ---------------
1265 -- Verify that node is not part of the type declaration for the
1266 -- candidate type, which would otherwise be invisible.
1268 -------------
1269 -- In_Decl --
1270 -------------
1276 begin
1285 else
1288 loop
1291 else
1300 -- Start of processing for Type_In_P
1302 begin
1303 -- If the context type is declared in the prefix package, this is the
1304 -- desired base type.
1309 else
1323 -- Start of processing for Make_Call_Into_Operator
1325 begin
1328 -- Binary operator
1338 -- Unary operator
1340 else
1346 -- If the operator is denoted by an expanded name, and the prefix is
1347 -- not Standard, but the operator is a predefined one whose scope is
1348 -- Standard, then this is an implicit_operator, inserted as an
1349 -- interpretation by the procedure of the same name. This procedure
1350 -- overestimates the presence of implicit operators, because it does
1351 -- not examine the type of the operands. Verify now that the operand
1352 -- type appears in the given scope. If right operand is universal,
1353 -- check the other operand. In the case of concatenation, either
1354 -- argument can be the component type, so check the type of the result.
1355 -- If both arguments are literals, look for a type of the right kind
1356 -- defined in the given scope. This elaborate nonsense is brought to
1357 -- you courtesy of b33302a. The type itself must be frozen, so we must
1358 -- find the type of the proper class in the given scope.
1360 -- A final wrinkle is the multiplication operator for fixed point types,
1361 -- which is defined in Standard only, and not in the scope of the
1362 -- fixed point type itself.
1367 -- If this is a package renaming, get renamed entity, which will be
1368 -- the scope of the operands if operaton is type-correct.
1374 -- If the entity being called is defined in the given package, it is
1375 -- a renaming of a predefined operator, and known to be legal.
1379 then
1382 -- Visibility does not need to be checked in an instance: if the
1383 -- operator was not visible in the generic it has been diagnosed
1384 -- already, else there is an implicit copy of it in the instance.
1392 then
1397 -- Ada 2005 AI-420: Predefined equality on Universal_Access is
1398 -- available.
1403 then
1406 else
1415 and then Is_Binary
1417 then
1423 -- Verify that the scope contains a type that corresponds to
1424 -- the given literal. Optimize the case where Pack is Standard.
1446 else
1455 else
1464 then
1467 -- If the type is defined elsewhere, and the operator is not
1468 -- defined in the given scope (by a renaming declaration, e.g.)
1469 -- then this is an error as well. If an extension of System is
1470 -- present, and the type may be defined there, Pack must be
1471 -- System itself.
1478 then
1481 else
1487 then
1494 Error_Msg_NE
1499 -- Detect a mismatch between the context type and the result type
1500 -- in the named package, which is otherwise not detected if the
1501 -- operands are universal. Check is only needed if source entity is
1502 -- an operator, not a function that renames an operator.
1509 and then not In_Instance
1510 then
1513 then
1514 -- Already checked above
1518 -- Operator may be defined in an extension of System
1522 then
1525 else
1526 -- Could we use Wrong_Type here??? (this would require setting
1527 -- Etype (N) to the actual type found where Typ was expected).
1538 else
1542 -- If this is a call to a function that renames a predefined equality,
1543 -- the renaming declaration provides a type that must be used to
1544 -- resolve the operands. This must be done now because resolution of
1545 -- the equality node will not resolve any remaining ambiguity, and it
1546 -- assumes that the first operand is not overloaded.
1551 then
1559 -- Do rewrite setting Comes_From_Source on the result if the original
1560 -- call came from source. Although it is not strictly the case that the
1561 -- operator as such comes from the source, logically it corresponds
1562 -- exactly to the function call in the source, so it should be marked
1563 -- this way (e.g. to make sure that validity checks work fine).
1565 declare
1567 begin
1572 -- If this is an arithmetic operator and the result type is private,
1573 -- the operands and the result must be wrapped in conversion to
1574 -- expose the underlying numeric type and expand the proper checks,
1575 -- e.g. on division.
1579 when N_Op_Add | N_Op_Subtract | N_Op_Multiply | N_Op_Divide |
1580 N_Op_Expon | N_Op_Mod | N_Op_Rem =>
1589 else
1593 -- If in ASIS_Mode, propagate operand types to original actuals of
1594 -- function call, which would otherwise not be fully resolved. If
1595 -- the call has already been constant-folded, nothing to do. We
1596 -- relocate the operand nodes rather than copy them, to preserve
1597 -- original_node pointers, given that the operands themselves may
1598 -- have been rewritten. If the call was itself a rewriting of an
1599 -- operator node, nothing to do.
1601 if ASIS_Mode
1604 then
1605 declare
1613 begin
1618 -- If the original call has named associations, replace the
1619 -- explicit actual parameter in the association with the proper
1620 -- resolved operand.
1625 then
1628 else
1633 else
1640 then
1643 else
1648 else
1652 else
1656 else
1666 -------------------
1667 -- Operator_Kind --
1668 -------------------
1670 function Operator_Kind
1673 is
1676 begin
1677 -- Use CASE statement or array???
1714 else
1718 -- Unary operators
1720 else
1729 else
1737 ----------------------------
1738 -- Preanalyze_And_Resolve --
1739 ----------------------------
1744 begin
1748 -- Normally, we suppress all checks for this preanalysis. There is no
1749 -- point in processing them now, since they will be applied properly
1750 -- and in the proper location when the default expressions reanalyzed
1751 -- and reexpanded later on. We will also have more information at that
1752 -- point for possible suppression of individual checks.
1754 -- However, in SPARK mode, most expansion is suppressed, and this
1755 -- later reanalysis and reexpansion may not occur. SPARK mode does
1756 -- require the setting of checking flags for proof purposes, so we
1757 -- do the SPARK preanalysis without suppressing checks.
1759 -- This special handling for SPARK mode is required for example in the
1760 -- case of Ada 2012 constructs such as quantified expressions, which are
1761 -- expanded in two separate steps.
1765 else
1769 Expander_Mode_Restore;
1773 -- Version without context type
1778 begin
1785 Expander_Mode_Restore;
1789 ----------------------------------
1790 -- Replace_Actual_Discriminants --
1791 ----------------------------------
1798 -- Comment needed???
1800 -------------------
1801 -- Process_Discr --
1802 -------------------
1807 begin
1813 then
1829 -- Start of processing for Replace_Actual_Discriminants
1831 begin
1845 else
1850 -------------
1851 -- Resolve --
1852 -------------
1868 -- Determine whether a node comes from a predefined library unit or
1869 -- Standard.
1872 -- Try and fix up a literal so that it matches its expected type. New
1873 -- literals are manufactured if necessary to avoid cascaded errors.
1876 -- Additional diagnostics when an ambiguous call has an ambiguous
1877 -- argument (typically a controlling actual).
1880 -- Called when attempt at resolving current expression fails
1882 ------------------------------------
1883 -- Comes_From_Predefined_Lib_Unit --
1884 -------------------------------------
1887 begin
1888 return
1890 or else Is_Predefined_File_Name
1894 --------------------
1895 -- Patch_Up_Value --
1896 --------------------
1899 begin
1916 then
1921 Char_Literal_Value =>
1937 -------------------------------
1938 -- Report_Ambiguous_Argument --
1939 -------------------------------
1946 begin
1950 then
1953 -- Could use comments on what is going on here???
1961 else
1970 -----------------------
1971 -- Resolution_Failed --
1972 -----------------------
1975 begin
1978 -- Set the type to the desired one to minimize cascaded errors. Note
1979 -- that this is an approximation and does not work in all cases.
1986 -- The caller will return without calling the expander, so we need
1987 -- to set the analyzed flag. Note that it is fine to set Analyzed
1988 -- to True even if we are in the middle of a shallow analysis,
1989 -- (see the spec of sem for more details) since this is an error
1990 -- situation anyway, and there is no point in repeating the
1991 -- analysis later (indeed it won't work to repeat it later, since
1992 -- we haven't got a clear resolution of which entity is being
1993 -- referenced.)
1999 -- Local variables
2003 -- Start of processing for Resolve
2005 begin
2010 -- A declaration may be subject to pragma Ghost. Set the mode now to
2011 -- ensure that any nodes generated during analysis and expansion are
2012 -- marked as Ghost.
2018 -- Access attribute on remote subprogram cannot be used for a non-remote
2019 -- access-to-subprogram type.
2023 Name_Unrestricted_Access,
2024 Name_Unchecked_Access)
2030 then
2031 Error_Msg_N
2037 -- If the context is a Remote_Access_To_Subprogram, access attributes
2038 -- must be resolved with the corresponding fat pointer. There is no need
2039 -- to check for the attribute name since the return type of an
2040 -- attribute is never a remote type.
2045 then
2046 declare
2054 begin
2055 -- Check that Typ is a remote access-to-subprogram type
2059 -- Prefix (N) must statically denote a remote subprogram
2060 -- declared in a package specification.
2064 Attr = Attribute_Unrestricted_Access
2065 then
2080 or else
2082 then
2084 Error_Msg_N
2086 N);
2089 -- If we are generating code in distributed mode, perform
2090 -- semantic checks against corresponding remote entities.
2092 if Expander_Active
2094 then
2095 Check_Subtype_Conformant
2097 Old_Id => Designated_Type
2123 then
2128 -- Return if already analyzed
2136 -- Any case of Any_Type as the Etype value means that we had a
2137 -- previous error.
2147 -- The resolution of an Expression_With_Actions is determined by
2148 -- its Expression.
2156 -- If not overloaded, then we know the type, and all that needs doing
2157 -- is to check that this type is compatible with the context.
2163 -- In the overloaded case, we must select the interpretation that
2164 -- is compatible with the context (i.e. the type passed to Resolve)
2166 else
2167 -- Loop through possible interpretations
2176 -- We are only interested in interpretations that are compatible
2177 -- with the expected type, any other interpretations are ignored.
2182 Write_Eol;
2185 else
2186 -- Skip the current interpretation if it is disabled by an
2187 -- abstract operator. This action is performed only when the
2188 -- type against which we are resolving is the same as the
2189 -- type of the interpretation.
2196 then
2204 -- First matching interpretation
2212 -- Matching interpretation that is not the first, maybe an
2213 -- error, but there are some cases where preference rules are
2214 -- used to choose between the two possibilities. These and
2215 -- some more obscure cases are handled in Disambiguate.
2217 else
2218 -- If the current statement is part of a predefined library
2219 -- unit, then all interpretations which come from user level
2220 -- packages should not be considered. Check previous and
2221 -- current one.
2229 -- Previous interpretation must be discarded
2239 -- Otherwise apply further disambiguation steps
2244 -- Disambiguation has succeeded. Skip the remaining
2245 -- interpretations.
2255 else
2256 -- Before we issue an ambiguity complaint, check for the
2257 -- case of a subprogram call where at least one of the
2258 -- arguments is Any_Type, and if so suppress the message,
2259 -- since it is a cascaded error. This can also happen for
2260 -- a generalized indexing operation.
2265 then
2266 declare
2270 begin
2286 Write_Eol;
2299 then
2304 then
2308 -- Not that special case, so issue message using the flag
2309 -- Ambiguous to control printing of the header message
2310 -- only at the start of an ambiguous set.
2315 then
2316 Error_Msg_N
2319 else
2320 Error_Msg_NE -- CODEFIX
2328 Error_Msg_N
2330 else
2331 Error_Msg_N -- CODEFIX
2337 then
2338 Report_Ambiguous_Argument;
2344 -- By default, the error message refers to the candidate
2345 -- interpretation. But if it is a predefined operator, it
2346 -- is implicitly declared at the declaration of the type
2347 -- of the operand. Recover the sloc of that declaration
2348 -- for the error message.
2354 Standard_Standard
2355 then
2360 then
2368 Standard_Standard
2369 then
2374 then
2378 -- If this is an indirect call, use the subprogram_type
2379 -- in the message, to have a meaningful location. Also
2380 -- indicate if this is an inherited operation, created
2381 -- by a type declaration.
2386 then
2388 Error_Msg_Sloc :=
2390 else
2397 then
2398 -- Special-case the message for universal_fixed
2399 -- operators, which are not declared with the type
2400 -- of the operand, but appear forever in Standard.
2404 then
2405 Error_Msg_N
2408 else
2409 Error_Msg_N
2413 elsif
2415 then
2416 Error_Msg_N
2418 else
2419 Error_Msg_N -- CODEFIX
2426 -- We have a matching interpretation, Expr_Type is the type
2427 -- from this interpretation, and Seen is the entity.
2429 -- For an operator, just set the entity name. The type will be
2430 -- set by the specific operator resolution routine.
2445 -- AI05-0139-2: Expression is overloaded because type has
2446 -- implicit dereference. If type matches context, no implicit
2447 -- dereference is involved.
2458 then
2459 -- If the node is a general indexing, the dereference is
2460 -- is inserted when resolving the rewritten form, else
2461 -- insert it now.
2465 then
2469 -- For an explicit dereference, attribute reference, range,
2470 -- short-circuit form (which is not an operator node), or call
2471 -- with a name that is an explicit dereference, there is
2472 -- nothing to be done at this point.
2475 N_Attribute_Reference,
2476 N_And_Then,
2477 N_Indexed_Component,
2478 N_Or_Else,
2479 N_Range,
2480 N_Selected_Component,
2481 N_Slice)
2483 then
2486 -- For procedure or function calls, set the type of the name,
2487 -- and also the entity pointer for the prefix.
2491 then
2498 then
2503 -- For all other cases, just set the type of the Name
2505 else
2513 -- Move to next interpretation
2521 -- At this stage Found indicates whether or not an acceptable
2522 -- interpretation exists. If not, then we have an error, except that if
2523 -- the context is Any_Type as a result of some other error, then we
2524 -- suppress the error report.
2529 -- If type we are looking for is Void, then this is the procedure
2530 -- call case, and the error is simply that what we gave is not a
2531 -- procedure name (we think of procedure calls as expressions with
2532 -- types internally, but the user doesn't think of them this way).
2536 -- Special case message if function used as a procedure
2541 then
2542 Error_Msg_NE
2546 -- Otherwise give general message (not clear what cases this
2547 -- covers, but no harm in providing for them).
2549 else
2555 -- Otherwise we do have a subexpression with the wrong type
2557 -- Check for the case of an allocator which uses an access type
2558 -- instead of the designated type. This is a common error and we
2559 -- specialize the message, posting an error on the operand of the
2560 -- allocator, complaining that we expected the designated type of
2561 -- the allocator.
2567 then
2571 -- Check for view mismatch on Null in instances, for which the
2572 -- view-swapping mechanism has no identifier.
2578 then
2584 -- Check for an aggregate. Sometimes we can get bogus aggregates
2585 -- from misuse of parentheses, and we are about to complain about
2586 -- the aggregate without even looking inside it.
2588 -- Instead, if we have an aggregate of type Any_Composite, then
2589 -- analyze and resolve the component fields, and then only issue
2590 -- another message if we get no errors doing this (otherwise
2591 -- assume that the errors in the aggregate caused the problem).
2595 then
2596 -- Disable expansion in any case. If there is a type mismatch
2597 -- it may be fatal to try to expand the aggregate. The flag
2598 -- would otherwise be set to false when the error is posted.
2602 declare
2604 -- Check one aggregate, and set Found to True if we have a
2605 -- definite error in any of its elements
2608 -- Check one element of aggregate and set Found to True if
2609 -- we definitely have an error in the element.
2611 ----------------
2612 -- Check_Aggr --
2613 ----------------
2618 begin
2631 -- If this is a default-initialized component, then
2632 -- there is nothing to check. The box will be
2633 -- replaced by the appropriate call during late
2634 -- expansion.
2645 ----------------
2646 -- Check_Elmt --
2647 ----------------
2650 begin
2651 -- If we have a nested aggregate, go inside it (to
2652 -- attempt a naked analyze-resolve of the aggregate can
2653 -- cause undesirable cascaded errors). Do not resolve
2654 -- expression if it needs a type from context, as for
2655 -- integer * fixed expression.
2660 else
2665 then
2675 begin
2680 -- Looks like we have a type error, but check for special case
2681 -- of Address wanted, integer found, with the configuration pragma
2682 -- Allow_Integer_Address active. If we have this case, introduce
2683 -- an unchecked conversion to allow the integer expression to be
2684 -- treated as an Address. The reverse case of integer wanted,
2685 -- Address found, is treated in an analogous manner.
2693 -- Under relaxed RM semantics silently replace occurrences of null
2694 -- by System.Address_Null.
2702 -- That special Allow_Integer_Address check did not apply, so we
2703 -- have a real type error. If an error message was issued already,
2704 -- Found got reset to True, so if it's still False, issue standard
2705 -- Wrong_Type message.
2709 declare
2712 begin
2718 -- Protected operation: retrieve operation name
2722 else
2727 Error_Msg_NE
2733 declare
2737 begin
2744 Error_Msg_NE
2750 else
2754 else
2760 Resolution_Failed;
2764 -- Test if we have more than one interpretation for the context
2767 Resolution_Failed;
2771 -- Only one intepretation
2773 else
2774 -- In Ada 2005, if we have something like "X : T := 2 + 2;", where
2775 -- the "+" on T is abstract, and the operands are of universal type,
2776 -- the above code will have (incorrectly) resolved the "+" to the
2777 -- universal one in Standard. Therefore check for this case and give
2778 -- an error. We can't do this earlier, because it would cause legal
2779 -- cases to get errors (when some other type has an abstract "+").
2785 then
2790 then
2791 Error_Msg_NE
2800 -- Here we have an acceptable interpretation for the context
2802 -- Propagate type information and normalize tree for various
2803 -- predefined operations. If the context only imposes a class of
2804 -- types, rather than a specific type, propagate the actual type
2805 -- downward.
2811 Typ = Any_Discrete
2812 then
2815 -- Any_Fixed is legal in a real context only if a specific fixed-
2816 -- point type is imposed. If Norman Cohen can be confused by this,
2817 -- it deserves a separate message.
2821 then
2828 -- A user-defined operator is transformed into a function call at
2829 -- this point, so that further processing knows that operators are
2830 -- really operators (i.e. are predefined operators). User-defined
2831 -- operators that are intrinsic are just renamings of the predefined
2832 -- ones, and need not be turned into calls either, but if they rename
2833 -- a different operator, we must transform the node accordingly.
2834 -- Instantiations of Unchecked_Conversion are intrinsic but are
2835 -- treated as functions, even if given an operator designator.
2840 then
2846 and then
2848 N_Subprogram_Renaming_Declaration
2849 then
2852 -- If the node is rewritten, it will be fully resolved in
2853 -- Rewrite_Renamed_Operator.
2864 when N_Aggregate => Resolve_Aggregate (N, Ctx_Type);
2866 when N_Allocator => Resolve_Allocator (N, Ctx_Type);
2868 when N_Short_Circuit
2869 => Resolve_Short_Circuit (N, Ctx_Type);
2871 when N_Attribute_Reference
2872 => Resolve_Attribute (N, Ctx_Type);
2874 when N_Case_Expression
2875 => Resolve_Case_Expression (N, Ctx_Type);
2877 when N_Character_Literal
2878 => Resolve_Character_Literal (N, Ctx_Type);
2880 when N_Expanded_Name
2881 => Resolve_Entity_Name (N, Ctx_Type);
2883 when N_Explicit_Dereference
2884 => Resolve_Explicit_Dereference (N, Ctx_Type);
2886 when N_Expression_With_Actions
2887 => Resolve_Expression_With_Actions (N, Ctx_Type);
2889 when N_Extension_Aggregate
2890 => Resolve_Extension_Aggregate (N, Ctx_Type);
2892 when N_Function_Call
2893 => Resolve_Call (N, Ctx_Type);
2895 when N_Identifier
2896 => Resolve_Entity_Name (N, Ctx_Type);
2898 when N_If_Expression
2899 => Resolve_If_Expression (N, Ctx_Type);
2901 when N_Indexed_Component
2902 => Resolve_Indexed_Component (N, Ctx_Type);
2904 when N_Integer_Literal
2905 => Resolve_Integer_Literal (N, Ctx_Type);
2907 when N_Membership_Test
2908 => Resolve_Membership_Op (N, Ctx_Type);
2910 when N_Null => Resolve_Null (N, Ctx_Type);
2912 when N_Op_And | N_Op_Or | N_Op_Xor
2913 => Resolve_Logical_Op (N, Ctx_Type);
2915 when N_Op_Eq | N_Op_Ne
2916 => Resolve_Equality_Op (N, Ctx_Type);
2918 when N_Op_Lt | N_Op_Le | N_Op_Gt | N_Op_Ge
2919 => Resolve_Comparison_Op (N, Ctx_Type);
2921 when N_Op_Not => Resolve_Op_Not (N, Ctx_Type);
2923 when N_Op_Add | N_Op_Subtract | N_Op_Multiply |
2924 N_Op_Divide | N_Op_Mod | N_Op_Rem
2926 => Resolve_Arithmetic_Op (N, Ctx_Type);
2928 when N_Op_Concat => Resolve_Op_Concat (N, Ctx_Type);
2930 when N_Op_Expon => Resolve_Op_Expon (N, Ctx_Type);
2932 when N_Op_Plus | N_Op_Minus | N_Op_Abs
2933 => Resolve_Unary_Op (N, Ctx_Type);
2935 when N_Op_Shift => Resolve_Shift (N, Ctx_Type);
2937 when N_Procedure_Call_Statement
2938 => Resolve_Call (N, Ctx_Type);
2940 when N_Operator_Symbol
2941 => Resolve_Operator_Symbol (N, Ctx_Type);
2943 when N_Qualified_Expression
2944 => Resolve_Qualified_Expression (N, Ctx_Type);
2946 -- Why is the following null, needs a comment ???
2948 when N_Quantified_Expression
2949 => null;
2951 when N_Raise_Expression
2952 => Resolve_Raise_Expression (N, Ctx_Type);
2954 when N_Raise_xxx_Error
2955 => Set_Etype (N, Ctx_Type);
2957 when N_Range => Resolve_Range (N, Ctx_Type);
2959 when N_Real_Literal
2960 => Resolve_Real_Literal (N, Ctx_Type);
2962 when N_Reference => Resolve_Reference (N, Ctx_Type);
2964 when N_Selected_Component
2965 => Resolve_Selected_Component (N, Ctx_Type);
2967 when N_Slice => Resolve_Slice (N, Ctx_Type);
2969 when N_String_Literal
2970 => Resolve_String_Literal (N, Ctx_Type);
2972 when N_Type_Conversion
2973 => Resolve_Type_Conversion (N, Ctx_Type);
2975 when N_Unchecked_Expression =>
2976 Resolve_Unchecked_Expression (N, Ctx_Type);
2978 when N_Unchecked_Type_Conversion =>
2979 Resolve_Unchecked_Type_Conversion (N, Ctx_Type);
2980 end case;
2982 -- Ada 2012 (AI05-0149): Apply an (implicit) conversion to an
2983 -- expression of an anonymous access type that occurs in the context
2984 -- of a named general access type, except when the expression is that
2985 -- of a membership test. This ensures proper legality checking in
2986 -- terms of allowed conversions (expressions that would be illegal to
2987 -- convert implicitly are allowed in membership tests).
2989 if Ada_Version >= Ada_2012
2990 and then Ekind (Ctx_Type) = E_General_Access_Type
2991 and then Ekind (Etype (N)) = E_Anonymous_Access_Type
2992 and then Nkind (Parent (N)) not in N_Membership_Test
2993 then
2994 Rewrite (N, Convert_To (Ctx_Type, Relocate_Node (N)));
2995 Analyze_And_Resolve (N, Ctx_Type);
2996 end if;
2998 -- If the subexpression was replaced by a non-subexpression, then
2999 -- all we do is to expand it. The only legitimate case we know of
3000 -- is converting procedure call statement to entry call statements,
3001 -- but there may be others, so we are making this test general.
3003 if Nkind (N) not in N_Subexpr then
3004 Debug_A_Exit ("resolving ", N, " (done)");
3005 Expand (N);
3006 Ghost_Mode := Save_Ghost_Mode;
3007 return;
3008 end if;
3010 -- The expression is definitely NOT overloaded at this point, so
3011 -- we reset the Is_Overloaded flag to avoid any confusion when
3012 -- reanalyzing the node.
3014 Set_Is_Overloaded (N, False);
3016 -- Freeze expression type, entity if it is a name, and designated
3017 -- type if it is an allocator (RM 13.14(10,11,13)).
3019 -- Now that the resolution of the type of the node is complete, and
3020 -- we did not detect an error, we can expand this node. We skip the
3021 -- expand call if we are in a default expression, see section
3022 -- "Handling of Default Expressions" in Sem spec.
3024 Debug_A_Exit ("resolving ", N, " (done)");
3026 -- We unconditionally freeze the expression, even if we are in
3027 -- default expression mode (the Freeze_Expression routine tests this
3028 -- flag and only freezes static types if it is set).
3030 -- Ada 2012 (AI05-177): The declaration of an expression function
3031 -- does not cause freezing, but we never reach here in that case.
3032 -- Here we are resolving the corresponding expanded body, so we do
3033 -- need to perform normal freezing.
3035 Freeze_Expression (N);
3037 -- Now we can do the expansion
3039 Expand (N);
3040 end if;
3042 Ghost_Mode := Save_Ghost_Mode;
3043 end Resolve;
3045 -------------
3046 -- Resolve --
3047 -------------
3049 -- Version with check(s) suppressed
3051 procedure Resolve (N : Node_Id; Typ : Entity_Id; Suppress : Check_Id) is
3052 begin
3053 if Suppress = All_Checks then
3054 declare
3055 Sva : constant Suppress_Array := Scope_Suppress.Suppress;
3056 begin
3057 Scope_Suppress.Suppress := (others => True);
3058 Resolve (N, Typ);
3059 Scope_Suppress.Suppress := Sva;
3060 end;
3062 else
3063 declare
3064 Svg : constant Boolean := Scope_Suppress.Suppress (Suppress);
3065 begin
3066 Scope_Suppress.Suppress (Suppress) := True;
3067 Resolve (N, Typ);
3068 Scope_Suppress.Suppress (Suppress) := Svg;
3069 end;
3070 end if;
3071 end Resolve;
3073 -------------
3074 -- Resolve --
3075 -------------
3077 -- Version with implicit type
3079 procedure Resolve (N : Node_Id) is
3080 begin
3081 Resolve (N, Etype (N));
3082 end Resolve;
3084 ---------------------
3085 -- Resolve_Actuals --
3086 ---------------------
3088 procedure Resolve_Actuals (N : Node_Id; Nam : Entity_Id) is
3089 Loc : constant Source_Ptr := Sloc (N);
3090 A : Node_Id;
3091 A_Id : Entity_Id;
3092 A_Typ : Entity_Id;
3093 F : Entity_Id;
3094 F_Typ : Entity_Id;
3095 Prev : Node_Id := Empty;
3096 Orig_A : Node_Id;
3097 Real_F : Entity_Id;
3099 Real_Subp : Entity_Id;
3100 -- If the subprogram being called is an inherited operation for
3101 -- a formal derived type in an instance, Real_Subp is the subprogram
3102 -- that will be called. It may have different formal names than the
3103 -- operation of the formal in the generic, so after actual is resolved
3104 -- the name of the actual in a named association must carry the name
3105 -- of the actual of the subprogram being called.
3107 procedure Check_Aliased_Parameter;
3108 -- Check rules on aliased parameters and related accessibility rules
3109 -- in (RM 3.10.2 (10.2-10.4)).
3111 procedure Check_Argument_Order;
3112 -- Performs a check for the case where the actuals are all simple
3113 -- identifiers that correspond to the formal names, but in the wrong
3114 -- order, which is considered suspicious and cause for a warning.
3116 procedure Check_Prefixed_Call;
3117 -- If the original node is an overloaded call in prefix notation,
3119 -- Try_Object_Operation has already verified that there is a valid
3120 -- interpretation, but the form of the actual can only be determined
3121 -- once the primitive operation is identified.
3124 -- Emit an error concerning the illegal usage of an effectively volatile
3125 -- object in interfering context (SPARK RM 7.13(12)).
3128 -- If the actual is missing in a call, insert in the actuals list
3129 -- an instance of the default expression. The insertion is always
3130 -- a named association.
3132 procedure Property_Error
3136 -- Emit an error concerning variable Var with entity Var_Id that has
3137 -- enabled property Prop_Nam when it acts as an actual parameter in a
3138 -- call and the corresponding formal parameter is of mode IN.
3141 -- Check whether T1 and T2, or their full views, are derived from a
3142 -- common type. Used to enforce the restrictions on array conversions
3143 -- of AI95-00246.
3146 -- Predicate to determine whether an actual that is a concatenation
3147 -- will be evaluated statically and does not need a transient scope.
3148 -- This must be determined before the actual is resolved and expanded
3149 -- because if needed the transient scope must be introduced earlier.
3151 -----------------------------
3152 -- Check_Aliased_Parameter --
3153 -----------------------------
3158 begin
3166 else
3173 -- In a generic body assume the worst for generic formals:
3174 -- they can have a constrained partial view (AI05-041).
3180 then
3183 else
3188 else
3200 then
3208 then
3209 Error_Msg_N
3215 --------------------------
3216 -- Check_Argument_Order --
3217 --------------------------
3220 begin
3221 -- Nothing to do if no parameters, or original node is neither a
3222 -- function call nor a procedure call statement (happens in the
3223 -- operator-transformed-to-function call case), or the call does
3224 -- not come from source, or this warning is off.
3226 if not Warn_On_Parameter_Order
3230 then
3234 declare
3237 begin
3238 -- Nothing to do if only one parameter
3244 -- Here if at least two arguments
3246 declare
3252 -- Set True if an out of order case is found
3254 begin
3255 -- Collect identifier names of actuals, fail if any actual is
3256 -- not a simple identifier, and record max length of name.
3262 else
3268 -- If we got this far, all actuals are identifiers and the list
3269 -- of their names is stored in the Actuals array.
3274 -- If we ran out of formals, that's odd, probably an error
3275 -- which will be detected elsewhere, but abandon the search.
3281 -- If name matches and is in order OK
3286 else
3287 -- If no match, see if it is elsewhere in list and if so
3288 -- flag potential wrong order if type is compatible.
3292 and then
3294 then
3300 -- No match
3308 -- If Formals left over, also probably an error, skip warning
3314 -- Here we give the warning if something was out of order
3317 Error_Msg_N
3324 -------------------------
3325 -- Check_Prefixed_Call --
3326 -------------------------
3335 begin
3336 -- Check whether the call is a prefixed call, with or without
3337 -- additional actuals.
3340 or else
3346 then
3349 then
3350 -- Introduce dereference on object in prefix
3352 New_A :=
3360 then
3361 -- Introduce an implicit 'Access in prefix
3364 Error_Msg_NE
3380 ---------------------------------------
3381 -- Flag_Effectively_Volatile_Objects --
3382 ---------------------------------------
3386 -- Determine whether arbitrary node N denotes an effectively volatile
3387 -- object and if it does, emit an error.
3389 -----------------
3390 -- Flag_Object --
3391 -----------------
3396 begin
3397 -- Do not consider nested function calls because they have already
3398 -- been processed during their own resolution.
3410 then
3411 Error_Msg_N
3423 -- Start of processing for Flag_Effectively_Volatile_Objects
3425 begin
3429 --------------------
3430 -- Insert_Default --
3431 --------------------
3437 begin
3438 -- Missing argument in call, nothing to insert
3443 else
3444 -- Note that we do a full New_Copy_Tree, so that any associated
3445 -- Itypes are properly copied. This may not be needed any more,
3446 -- but it does no harm as a safety measure. Defaults of a generic
3447 -- formal may be out of bounds of the corresponding actual (see
3448 -- cc1311b) and an additional check may be required.
3450 Actval :=
3451 New_Copy_Tree
3456 -- Propagate dimension information, if any.
3462 then
3468 then
3471 then
3472 -- If default is a real literal, do not introduce a
3473 -- conversion whose effect may depend on the run-time
3474 -- size of universal real.
3478 else
3489 -- Resolve aggregates with their base type, to avoid scope
3490 -- anomalies: the subtype was first built in the subprogram
3491 -- declaration, and the current call may be nested.
3495 else
3499 else
3502 -- See note above concerning aggregates
3506 then
3509 -- Resolve entities with their own type, which may differ from
3510 -- the type of a reference in a generic context (the view
3511 -- swapping mechanism did not anticipate the re-analysis of
3512 -- default values in calls).
3517 else
3522 -- If default is a tag indeterminate function call, propagate tag
3523 -- to obtain proper dispatching.
3527 then
3532 -- If the default expression raises constraint error, then just
3533 -- silently replace it with an N_Raise_Constraint_Error node, since
3534 -- we already gave the warning on the subprogram spec. If node is
3535 -- already a Raise_Constraint_Error leave as is, to prevent loops in
3536 -- the warnings removal machinery.
3540 then
3548 Assoc :=
3553 -- Case of insertion is first named actual
3557 then
3564 else
3568 else
3572 -- Case of insertion is not first named actual
3574 else
3575 Set_Next_Named_Actual
3587 --------------------
3588 -- Property_Error --
3589 --------------------
3591 procedure Property_Error
3595 is
3596 begin
3598 Error_Msg_NE
3604 -------------------
3605 -- Same_Ancestor --
3606 -------------------
3612 begin
3615 then
3621 then
3628 --------------------------
3629 -- Static_Concatenation --
3630 --------------------------
3633 begin
3640 -- Concatenation is static when both operands are static and
3641 -- the concatenation operator is a predefined one.
3644 and then
3646 and then
3651 declare
3653 begin
3656 and then
3660 else
3666 -- Start of processing for Resolve_Actuals
3668 begin
3669 Check_Argument_Order;
3673 and then In_Instance
3676 then
3678 else
3683 Check_Prefixed_Call;
3697 -- If we have an error in any actual or formal, indicated by a type
3698 -- of Any_Type, then abandon resolution attempt, and set result type
3699 -- to Any_Type. Skip this if the actual is a Raise_Expression, whose
3700 -- type is imposed from context.
3704 then
3711 -- Case where actual is present
3713 -- If the actual is an entity, generate a reference to it now. We
3714 -- do this before the actual is resolved, because a formal of some
3715 -- protected subprogram, or a task discriminant, will be rewritten
3716 -- during expansion, and the source entity reference may be lost.
3721 then
3727 then
3734 -- RM 6.4.1(12): For an out parameter that is passed by
3735 -- copy, the formal parameter object is created, and:
3737 -- * For an access type, the formal parameter is initialized
3738 -- from the value of the actual, without checking that the
3739 -- value satisfies any constraint, any predicate, or any
3740 -- exclusion of the null value.
3742 -- * For a scalar type that has the Default_Value aspect
3743 -- specified, the formal parameter is initialized from the
3744 -- value of the actual, without checking that the value
3745 -- satisfies any constraint or any predicate.
3746 -- I do not understand why this case is included??? this is
3747 -- not a case where an OUT parameter is treated as IN OUT.
3749 -- * For a composite type with discriminants or that has
3750 -- implicit initial values for any subcomponents, the
3751 -- behavior is as for an in out parameter passed by copy.
3753 -- Hence for these cases we generate the read reference now
3754 -- (the write reference will be generated later by
3755 -- Note_Possible_Modification).
3758 and then
3760 or else
3762 and then
3764 or else
3767 or else Is_Partially_Initialized_Type
3769 then
3779 then
3780 -- If style checking mode on, check match of formal name
3788 -- If the formal is Out or In_Out, do not resolve and expand the
3789 -- conversion, because it is subsequently expanded into explicit
3790 -- temporaries and assignments. However, the object of the
3791 -- conversion can be resolved. An exception is the case of tagged
3792 -- type conversion with a class-wide actual. In that case we want
3793 -- the tag check to occur and no temporary will be needed (no
3794 -- representation change can occur) and the parameter is passed by
3795 -- reference, so we go ahead and resolve the type conversion.
3796 -- Another exception is the case of reference to component or
3797 -- subcomponent of a bit-packed array, in which case we want to
3798 -- defer expansion to the point the in and out assignments are
3799 -- performed.
3804 then
3807 then
3808 -- In a view conversion, the conversion must be legal in
3809 -- both directions, and thus both component types must be
3810 -- aliased, or neither (4.6 (8)).
3812 -- The extra rule in 4.6 (24.9.2) seems unduly restrictive:
3813 -- the privacy requirement should not apply to generic
3814 -- types, and should be checked in an instance. ARG query
3815 -- is in order ???
3819 then
3820 Error_Msg_N
3824 -- Comment here??? what set of cases???
3826 elsif
3828 then
3829 -- Check view conv between unrelated by ref array types
3833 then
3834 Error_Msg_N
3838 -- In Ada 2005 mode, check view conversion component
3839 -- type cannot be private, tagged, or volatile. Note
3840 -- that we only apply this to source conversions. The
3841 -- generated code can contain conversions which are
3842 -- not subject to this test, and we cannot extract the
3843 -- component type in such cases since it is not present.
3847 then
3848 declare
3850 Component_Type
3852 begin
3857 then
3858 Error_Msg_N
3869 -- Resolve expression if conversion is all OK
3874 then
3878 -- If the actual is a function call that returns a limited
3879 -- unconstrained object that needs finalization, create a
3880 -- transient scope for it, so that it can receive the proper
3881 -- finalization list.
3886 and then Expander_Active
3888 then
3892 -- A small optimization: if one of the actuals is a concatenation
3893 -- create a block around a procedure call to recover stack space.
3894 -- This alleviates stack usage when several procedure calls in
3895 -- the same statement list use concatenation. We do not perform
3896 -- this wrapping for code statements, where the argument is a
3897 -- static string, and we want to preserve warnings involving
3898 -- sequences of such statements.
3902 and then Expander_Active
3903 and then
3907 then
3911 else
3915 and then
3918 then
3919 Error_Msg_N
3932 -- (Ada 2005: AI-251): If the actual is an allocator whose
3933 -- directly designated type is a class-wide interface, we build
3934 -- an anonymous access type to use it as the type of the
3935 -- allocator. Later, when the subprogram call is expanded, if
3936 -- the interface has a secondary dispatch table the expander
3937 -- will add a type conversion to force the correct displacement
3938 -- of the pointer.
3941 declare
3947 begin
3950 then
3953 Set_Directly_Designated_Type
3958 -- Ada 2005, AI-162:If the actual is an allocator, the
3959 -- innermost enclosing statement is the master of the
3960 -- created object. This needs to be done with expansion
3961 -- enabled only, otherwise the transient scope will not
3962 -- be removed in the expansion of the wrapped construct.
3965 and then Expander_Active
3966 then
3976 -- (Ada 2005): The call may be to a primitive operation of a
3977 -- tagged synchronized type, declared outside of the type. In
3978 -- this case the controlling actual must be converted to its
3979 -- corresponding record type, which is the formal type. The
3980 -- actual may be a subtype, either because of a constraint or
3981 -- because it is a generic actual, so use base type to locate
3982 -- concurrent type.
3989 then
3990 -- If the actual is overloaded, look for an interpretation
3991 -- that has a synchronized type.
3996 else
3997 declare
4001 begin
4006 then
4016 declare
4019 begin
4022 else
4026 -- Tagged synchronized type (case 1): the actual is a
4027 -- concurrent type.
4031 then
4033 Unchecked_Convert_To
4037 -- Tagged synchronized type (case 2): the formal is a
4038 -- concurrent type.
4041 and then Present
4046 then
4049 -- Common case
4051 else
4056 -- Not a synchronized operation
4058 else
4066 -- An actual cannot be an untagged formal incomplete type
4071 then
4072 Error_Msg_N
4078 N_Procedure_Call_Statement)
4079 then
4080 -- In formal mode, check that actual parameters matching
4081 -- formals of tagged types are objects (or ancestor type
4082 -- conversions of objects), not general expressions.
4089 declare
4094 begin
4096 Check_SPARK_05_Restriction
4099 -- In formal mode, the only view conversions are those
4100 -- involving ancestor conversion of an extended type.
4102 elsif not
4108 then
4109 if Ekind_In
4111 then
4112 Check_SPARK_05_Restriction
4115 else
4116 Check_SPARK_05_Restriction
4120 else
4125 else
4129 -- In formal mode, the only view conversions are those
4130 -- involving ancestor conversion of an extended type.
4134 then
4135 Check_SPARK_05_Restriction
4141 -- has warnings suppressed, then we reset Never_Set_In_Source for
4142 -- the calling entity. The reason for this is to catch cases like
4143 -- GNAT.Spitbol.Patterns.Vstring_Var where the called subprogram
4144 -- uses trickery to modify an IN parameter.
4151 then
4155 -- Perform error checks for IN and IN OUT parameters
4159 -- Check unset reference. For scalar parameters, it is clearly
4160 -- wrong to pass an uninitialized value as either an IN or
4161 -- IN-OUT parameter. For composites, it is also clearly an
4162 -- error to pass a completely uninitialized value as an IN
4163 -- parameter, but the case of IN OUT is trickier. We prefer
4164 -- not to give a warning here. For example, suppose there is
4165 -- a routine that sets some component of a record to False.
4166 -- It is perfectly reasonable to make this IN-OUT and allow
4167 -- either initialized or uninitialized records to be passed
4168 -- in this case.
4170 -- For partially initialized composite values, we also avoid
4171 -- warnings, since it is quite likely that we are passing a
4172 -- partially initialized value and only the initialized fields
4173 -- will in fact be read in the subprogram.
4178 then
4182 -- In Ada 83 we cannot pass an OUT parameter as an IN or IN OUT
4183 -- actual to a nested call, since this constitutes a reading of
4184 -- the parameter, which is not allowed.
4189 then
4194 -- Case of OUT or IN OUT parameter
4198 -- For an Out parameter, check for useless assignment. Note
4199 -- that we can't set Last_Assignment this early, because we may
4200 -- kill current values in Resolve_Call, and that call would
4201 -- clobber the Last_Assignment field.
4203 -- Note: call Warn_On_Useless_Assignment before doing the check
4204 -- below for Is_OK_Variable_For_Out_Formal so that the setting
4205 -- of Referenced_As_LHS/Referenced_As_Out_Formal properly
4206 -- reflects the last assignment, not this one.
4213 then
4218 -- Validate the form of the actual. Note that the call to
4219 -- Is_OK_Variable_For_Out_Formal generates the required
4220 -- reference in this case.
4222 -- A call to an initialization procedure for an aggregate
4223 -- component may initialize a nested component of a constant
4224 -- designated object. In this context the object is variable.
4228 then
4234 then
4235 Error_Msg_N
4240 Error_Msg_N
4247 -- What's the following about???
4251 else
4252 Kill_All_Checks;
4261 -- Apply appropriate constraint/predicate checks for IN [OUT] case
4265 -- Apply predicate tests except in certain special cases. Note
4266 -- that it might be more consistent to apply these only when
4267 -- expansion is active (in Exp_Ch6.Expand_Actuals), as we do
4268 -- for the outbound predicate tests ???
4274 -- Apply required constraint checks
4276 -- Gigi looks at the check flag and uses the appropriate types.
4277 -- For now since one flag is used there is an optimization
4278 -- which might not be done in the IN OUT case since Gigi does
4279 -- not do any analysis. More thought required about this ???
4281 -- In fact is this comment obsolete??? doesn't the expander now
4282 -- generate all these tests anyway???
4295 then
4298 -- For view conversions of a discriminated object, apply
4299 -- check to object itself, the conversion alreay has the
4300 -- proper type.
4304 then
4311 then
4317 then
4320 else
4324 -- Ada 2005 (AI-231): Note that the controlling parameter case
4325 -- already existed in Ada 95, which is partially checked
4326 -- elsewhere (see Checks), and we don't want the warning
4327 -- message to differ.
4332 then
4334 Apply_Compile_Time_Constraint_Error
4340 Apply_Compile_Time_Constraint_Error
4349 -- Checks for OUT parameters and IN OUT parameters
4353 -- If there is a type conversion, to make sure the return value
4354 -- meets the constraints of the variable before the conversion.
4358 Apply_Scalar_Range_Check
4360 else
4361 Apply_Range_Check
4365 -- If no conversion apply scalar range checks and length checks
4366 -- base on the subtype of the actual (NOT that of the formal).
4368 else
4373 then
4375 else
4380 -- Note: we do not apply the predicate checks for the case of
4381 -- OUT and IN OUT parameters. They are instead applied in the
4382 -- Expand_Actuals routine in Exp_Ch6.
4385 -- An actual associated with an access parameter is implicitly
4386 -- converted to the anonymous access type of the formal and must
4387 -- satisfy the legality checks for access conversions.
4391 Error_Msg_N
4395 -- If the actual is an access selected component of a variable,
4396 -- the call may modify its designated object. It is reasonable
4397 -- to treat this as a potential modification of the enclosing
4398 -- record, to prevent spurious warnings that it should be
4399 -- declared as a constant, because intuitively programmers
4400 -- regard the designated subcomponent as part of the record.
4405 then
4410 -- Check bad case of atomic/volatile argument (RM C.6(12))
4414 then
4417 then
4418 Error_Msg_NE
4424 then
4425 Error_Msg_NE
4431 -- Check that subprograms don't have improper controlling
4432 -- arguments (RM 3.9.2 (9)).
4434 -- A primitive operation may have an access parameter of an
4435 -- incomplete tagged type, but a dispatching call is illegal
4436 -- if the type is still incomplete.
4442 declare
4444 begin
4448 then
4449 Error_Msg_NE
4460 -- Apply legality rule 3.9.2 (9/1)
4465 and then not In_Instance
4466 then
4471 Error_Msg_NE
4475 -- Apply the checks described in 3.10.2(27): if the context is a
4476 -- specific access-to-object, the actual cannot be class-wide.
4477 -- Use base type to exclude access_to_subprogram cases.
4484 and then
4489 -- Disable these checks for call to imported C++ subprograms
4491 and then not
4495 then
4496 Error_Msg_N
4501 Error_Msg_NE
4506 Check_Aliased_Parameter;
4510 -- If it is a named association, treat the selector_name as a
4511 -- proper identifier, and mark the corresponding entity.
4515 -- Ignore reference in SPARK mode, as it refers to an entity not
4516 -- in scope at the point of reference, so the reference should
4517 -- be ignored for computing effects of subprograms.
4519 and then not GNATprove_Mode
4520 then
4521 -- If subprogram is overridden, use name of formal that
4522 -- is being called.
4528 else
4542 -- The following checks are only relevant when SPARK_Mode is on as
4543 -- they are not standard Ada legality rule. Internally generated
4544 -- temporaries are ignored.
4548 -- An effectively volatile object may act as an actual when the
4549 -- corresponding formal is of a non-scalar effectively volatile
4550 -- type (SPARK RM 7.1.3(11)).
4554 then
4557 -- An effectively volatile object may act as an actual in a
4558 -- call to an instance of Unchecked_Conversion.
4559 -- (SPARK RM 7.1.3(11)).
4564 -- The actual denotes an object
4567 Error_Msg_N
4571 -- Otherwise the actual denotes an expression. Inspect the
4572 -- expression and flag each effectively volatile object with
4573 -- enabled property Async_Writers or Effective_Reads as illegal
4574 -- because it apprears within an interfering context. Note that
4575 -- this is usually done in Resolve_Entity_Name, but when the
4576 -- effectively volatile object appears as an actual in a call,
4577 -- the call must be resolved first.
4579 else
4583 -- Detect an external variable with an enabled property that
4584 -- does not match the mode of the corresponding formal in a
4585 -- procedure call. Functions are not considered because they
4586 -- cannot have effectively volatile formal parameters in the
4587 -- first place.
4594 then
4607 -- A formal parameter of a specific tagged type whose related
4608 -- subprogram is subject to pragma Extensions_Visible with value
4609 -- "False" cannot act as an actual in a subprogram with value
4610 -- "True" (SPARK RM 6.1.7(3)).
4614 Extensions_Visible_True
4615 then
4616 Error_Msg_N
4619 Error_Msg_NE
4623 -- The actual parameter of a Ghost subprogram whose formal is of
4624 -- mode IN OUT or OUT must be a Ghost variable (SPARK RM 6.9(12)).
4632 then
4633 Error_Msg_NE
4639 else
4646 -- Case where actual is not present
4648 else
4649 Insert_Default;
4660 -----------------------
4661 -- Resolve_Allocator --
4662 -----------------------
4674 procedure Check_Allocator_Discrim_Accessibility
4677 -- Check that accessibility level associated with an access discriminant
4678 -- initialized in an allocator by the expression Disc_Exp is not deeper
4679 -- than the level of the allocator type Alloc_Typ. An error message is
4680 -- issued if this condition is violated. Specialized checks are done for
4681 -- the cases of a constraint expression which is an access attribute or
4682 -- an access discriminant.
4685 -- If the allocator is an actual in a call, it is allowed to be class-
4686 -- wide when the context is not because it is a controlling actual.
4688 -------------------------------------------
4689 -- Check_Allocator_Discrim_Accessibility --
4690 -------------------------------------------
4692 procedure Check_Allocator_Discrim_Accessibility
4695 is
4696 begin
4699 then
4700 Error_Msg_N
4703 -- When the expression is an Access attribute the level of the prefix
4704 -- object must not be deeper than that of the allocator's type.
4708 Attribute_Access
4711 then
4712 Error_Msg_N
4714 Disc_Exp);
4716 -- When the expression is an access discriminant the check is against
4717 -- the level of the prefix object.
4723 then
4724 Error_Msg_N
4726 Disc_Exp);
4728 -- All other cases are legal
4730 else
4735 ----------------------------
4736 -- In_Dispatching_Context --
4737 ----------------------------
4742 begin
4748 -- Start of processing for Resolve_Allocator
4750 begin
4751 -- Replace general access with specific type
4761 -- For qualified expression, resolve the expression using the given
4762 -- subtype (nothing to do for type mark, subtype indication)
4767 and then not In_Dispatching_Context
4768 then
4769 Error_Msg_N
4777 -- Allocators generated by the build-in-place expansion mechanism
4778 -- are explicitly marked as coming from source but do not need to be
4779 -- checked for limited initialization. To exclude this case, ensure
4780 -- that the parent of the allocator is a source node.
4785 and then not In_Instance_Body
4786 then
4789 Error_Msg_N
4792 else
4793 Error_Msg_N
4801 -- A qualified expression requires an exact match of the type. Class-
4802 -- wide matching is not allowed.
4807 then
4811 -- Calls to build-in-place functions are not currently supported in
4812 -- allocators for access types associated with a simple storage pool.
4813 -- Supporting such allocators may require passing additional implicit
4814 -- parameters to build-in-place functions (or a significant revision
4815 -- of the current b-i-p implementation to unify the handling for
4816 -- multiple kinds of storage pools). ???
4820 then
4821 declare
4824 begin
4826 and then
4827 Present (Get_Rep_Pragma
4829 then
4830 Error_Msg_N
4837 -- A special accessibility check is needed for allocators that
4838 -- constrain access discriminants. The level of the type of the
4839 -- expression used to constrain an access discriminant cannot be
4840 -- deeper than the type of the allocator (in contrast to access
4841 -- parameters, where the level of the actual can be arbitrary).
4843 -- We can't use Valid_Conversion to perform this check because in
4844 -- general the type of the allocator is unrelated to the type of
4845 -- the access discriminant.
4849 then
4856 then
4859 -- Get the first component expression of the aggregate
4869 else
4873 else
4892 else
4897 else
4906 -- For a subtype mark or subtype indication, freeze the subtype
4908 else
4912 Error_Msg_N
4916 -- A special accessibility check is needed for allocators that
4917 -- constrain access discriminants. The level of the type of the
4918 -- expression used to constrain an access discriminant cannot be
4919 -- deeper than the type of the allocator (in contrast to access
4920 -- parameters, where the level of the actual can be arbitrary).
4921 -- We can't use Valid_Conversion to perform this check because
4922 -- in general the type of the allocator is unrelated to the type
4923 -- of the access discriminant.
4928 then
4938 else
4952 -- Ada 2005 (AI-344): A class-wide allocator requires an accessibility
4953 -- check that the level of the type of the created object is not deeper
4954 -- than the level of the allocator's access type, since extensions can
4955 -- now occur at deeper levels than their ancestor types. This is a
4956 -- static accessibility level check; a run-time check is also needed in
4957 -- the case of an initialized allocator with a class-wide argument (see
4958 -- Expand_Allocator_Expression).
4962 then
4963 declare
4966 begin
4971 else
4977 then
4980 Error_Msg_N
4989 -- Do not apply Ada 2005 accessibility checks on a class-wide
4990 -- allocator if the type given in the allocator is a formal
4991 -- type. A run-time check will be performed in the instance.
5001 -- Check for allocation from an empty storage pool
5006 -- If the context is an unchecked conversion, as may happen within an
5007 -- inlined subprogram, the allocator is being resolved with its own
5008 -- anonymous type. In that case, if the target type has a specific
5009 -- storage pool, it must be inherited explicitly by the allocator type.
5013 then
5014 Set_Associated_Storage_Pool
5022 -- Check that an allocator with task parts isn't for a nested access
5023 -- type when restriction No_Task_Hierarchy applies.
5027 then
5031 -- An illegal allocator may be rewritten as a raise Program_Error
5032 -- statement.
5036 -- An anonymous access discriminant is the definition of a
5037 -- coextension.
5041 N_Discriminant_Specification
5042 then
5043 declare
5047 begin
5050 -- Ada 2012 AI05-0052: If the designated type of the allocator
5051 -- is limited, then the allocator shall not be used to define
5052 -- the value of an access discriminant unless the discriminated
5053 -- type is immutably limited.
5058 then
5059 Error_Msg_N
5065 -- Avoid marking an allocator as a dynamic coextension if it is
5066 -- within a static construct.
5072 -- Cleanup for potential static coextensions
5074 else
5080 -- Report a simple error: if the designated object is a local task,
5081 -- its body has not been seen yet, and its activation will fail an
5082 -- elaboration check.
5089 then
5095 -- Ada 2012 (AI05-0111-3): Detect an attempt to allocate a task or a
5096 -- type with a task component on a subpool. This action must raise
5097 -- Program_Error at runtime.
5103 then
5115 ---------------------------
5116 -- Resolve_Arithmetic_Op --
5117 ---------------------------
5119 -- Used for resolving all arithmetic operators except exponentiation
5130 -- We do the resolution using the base type, because intermediate values
5131 -- in expressions always are of the base type, not a subtype of it.
5134 -- Returns True if N is in a context that expects "any real type"
5137 -- Return True iff given type is Integer or universal real/integer
5140 -- Choose type of integer literal in fixed-point operation to conform
5141 -- to available fixed-point type. T is the type of the other operand,
5142 -- which is needed to determine the expected type of N.
5145 -- Set operand type to T if universal
5147 -------------------------------
5148 -- Expected_Type_Is_Any_Real --
5149 -------------------------------
5152 begin
5153 -- N is the expression after "delta" in a fixed_point_definition;
5154 -- see RM-3.5.9(6):
5157 N_Decimal_Fixed_Point_Definition,
5159 -- N is one of the bounds in a real_range_specification;
5160 -- see RM-3.5.7(5):
5162 N_Real_Range_Specification,
5164 -- N is the expression of a delta_constraint;
5165 -- see RM-J.3(3):
5167 N_Delta_Constraint);
5170 -----------------------------
5171 -- Is_Integer_Or_Universal --
5172 -----------------------------
5179 begin
5185 else
5191 then
5202 ----------------------------
5203 -- Set_Mixed_Mode_Operand --
5204 ----------------------------
5210 begin
5213 -- A universal integer literal is resolved as standard integer
5214 -- except in the case of a fixed-point result, where we leave it
5215 -- as universal (to be handled by Exp_Fixd later on)
5219 else
5227 then
5228 -- A universal real can appear in a fixed-type context. We resolve
5229 -- the literal with that context, even though this might raise an
5230 -- exception prematurely (the other operand may be zero).
5237 then
5238 -- Integer arg in mixed-mode operation. Resolve with universal
5239 -- type, in case preference rule must be applied.
5245 then
5246 -- Not a mixed-mode operation, resolve with context
5252 -- N may itself be a mixed-mode operation, so use context type
5259 then
5260 -- Must be (fixed * fixed) operation, operand must have one
5261 -- compatible interpretation.
5268 then
5269 -- C * F(X) in a fixed context, where C is a real literal or a
5270 -- fixed-point expression. F must have either a fixed type
5271 -- interpretation or an integer interpretation, but not both.
5278 else
5285 else
5293 -- Reanalyze the literal with the fixed type of the context. If
5294 -- context is Universal_Fixed, we are within a conversion, leave
5295 -- the literal as a universal real because there is no usable
5296 -- fixed type, and the target of the conversion plays no role in
5297 -- the resolution.
5299 declare
5303 begin
5306 else
5312 then
5314 else
5322 else
5327 ----------------------
5328 -- Set_Operand_Type --
5329 ----------------------
5332 begin
5335 then
5340 -- Start of processing for Resolve_Arithmetic_Op
5342 begin
5347 then
5351 -- Special-case for mixed-mode universal expressions or fixed point type
5352 -- operation: each argument is resolved separately. The same treatment
5353 -- is required if one of the operands of a fixed point operation is
5354 -- universal real, since in this case we don't do a conversion to a
5355 -- specific fixed-point type (instead the expander handles the case).
5357 -- Set the type of the node to its universal interpretation because
5358 -- legality checks on an exponentiation operand need the context.
5363 then
5374 or else
5377 then
5382 -- If context is a fixed type and one operand is integer, the other
5383 -- is resolved with the type of the context.
5388 then
5395 then
5399 else
5404 -- Check the rule in RM05-4.5.5(19.1/2) disallowing universal_fixed
5405 -- multiplying operators from being used when the expected type is
5406 -- also universal_fixed. Note that B_Typ will be Universal_Fixed in
5407 -- some cases where the expected type is actually Any_Real;
5408 -- Expected_Type_Is_Any_Real takes care of that case.
5412 then
5416 N_Unchecked_Type_Conversion)
5417 then
5424 else
5427 and then not
5429 N_Unchecked_Type_Conversion)
5430 then
5431 Error_Msg_N
5436 -- The expected type is "any real type" in contexts like
5438 -- type T is delta <universal_fixed-expression> ...
5440 -- in which case we need to set the type to Universal_Real
5441 -- so that static expression evaluation will work properly.
5445 else
5455 then
5460 -- If no previous errors, this is only possible if one operand is
5461 -- overloaded and the context is universal. Resolve as such.
5466 else
5468 and then
5470 then
5474 -- If the context is Universal_Fixed and the operands are also
5475 -- universal fixed, this is an error, unless there is only one
5476 -- applicable fixed_point type (usually Duration).
5484 else
5489 else
5494 -- If one of the arguments was resolved to a non-universal type.
5495 -- label the result of the operation itself with the same type.
5496 -- Do the same for the universal argument, if any.
5508 -- In SPARK, a multiplication or division with operands of fixed point
5509 -- types must be qualified or explicitly converted to identify the
5510 -- result type.
5515 and then
5517 then
5518 Check_SPARK_05_Restriction
5522 -- Set overflow and division checking bit
5529 -- Give warning if explicit division by zero
5533 then
5539 or else
5542 then
5543 -- Specialize the warning message according to the operation.
5544 -- When SPARK_Mode is On, force a warning instead of an error
5545 -- in that case, as this likely corresponds to deactivated
5546 -- code. The following warnings are for the case
5551 -- For division, we have two cases, for float division
5552 -- of an unconstrained float type, on a machine where
5553 -- Machine_Overflows is false, we don't get an exception
5554 -- at run-time, but rather an infinity or Nan. The Nan
5555 -- case is pretty obscure, so just warn about infinities.
5559 and then not Machine_Overflows_On_Target
5560 then
5561 Error_Msg_N
5565 -- For all other cases, we get a Constraint_Error
5567 else
5568 Apply_Compile_Time_Constraint_Error
5575 Apply_Compile_Time_Constraint_Error
5581 Apply_Compile_Time_Constraint_Error
5586 -- Division by zero can only happen with division, rem,
5587 -- and mod operations.
5593 -- In GNATprove mode, we enable the division check so that
5594 -- GNATprove will issue a message if it cannot be proved.
5600 -- Otherwise just set the flag to check at run time
5602 else
5607 -- If Restriction No_Implicit_Conditionals is active, then it is
5608 -- violated if either operand can be negative for mod, or for rem
5609 -- if both operands can be negative.
5613 then
5614 declare
5621 -- Set if corresponding operand might be negative
5623 begin
5624 Determine_Range
5628 Determine_Range
5632 -- Check if we will be generating conditionals. There are two
5633 -- cases where that can happen, first for REM, the only case
5634 -- is largest negative integer mod -1, where the division can
5635 -- overflow, but we still have to give the right result. The
5636 -- front end generates a test for this annoying case. Here we
5637 -- just test if both operands can be negative (that's what the
5638 -- expander does, so we match its logic here).
5640 -- The second case is mod where either operand can be negative.
5641 -- In this case, the back end has to generate additional tests.
5644 or else
5646 then
5657 ------------------
5658 -- Resolve_Call --
5659 ------------------
5662 function Same_Or_Aliased_Subprograms
5665 -- Returns True if the subprogram entity S is the same as E or else
5666 -- S is an alias of E.
5668 ---------------------------------
5669 -- Same_Or_Aliased_Subprograms --
5670 ---------------------------------
5672 function Same_Or_Aliased_Subprograms
5675 is
5677 begin
5681 -- Local variables
5695 -- Start of processing for Resolve_Call
5697 begin
5698 -- The context imposes a unique interpretation with type Typ on a
5699 -- procedure or function call. Find the entity of the subprogram that
5700 -- yields the expected type, and propagate the corresponding formal
5701 -- constraints on the actuals. The caller has established that an
5702 -- interpretation exists, and emitted an error if not unique.
5704 -- First deal with the case of a call to an access-to-subprogram,
5705 -- dereference made explicit in Analyze_Call.
5711 else
5712 -- Find the interpretation whose type (a subprogram type) has a
5713 -- return type that is compatible with the context. Analysis of
5714 -- the node has established that one exists.
5733 -- If the prefix is not an entity, then resolve it
5739 -- For an indirect call, we always invalidate checks, since we do not
5740 -- know whether the subprogram is local or global. Yes we could do
5741 -- better here, e.g. by knowing that there are no local subprograms,
5742 -- but it does not seem worth the effort. Similarly, we kill all
5743 -- knowledge of current constant values.
5745 Kill_Current_Values;
5747 -- If this is a procedure call which is really an entry call, do
5748 -- the conversion of the procedure call to an entry call. Protected
5749 -- operations use the same circuitry because the name in the call
5750 -- can be an arbitrary expression with special resolution rules.
5755 then
5759 -- Kill checks and constant values, as above for indirect case
5760 -- Who knows what happens when another task is activated?
5762 Kill_Current_Values;
5765 -- Normal subprogram call with name established in Resolve
5771 -- Otherwise we must have the case of an overloaded call
5773 else
5776 -- Initialize Nam to prevent warning (we know it will be assigned
5777 -- in the loop below, but the compiler does not know that).
5797 then
5798 -- The prefix is a parameterless function call that returns an access
5799 -- to subprogram. If parameters are present in the current call, add
5800 -- add an explicit dereference. We use the base type here because
5801 -- within an instance these may be subtypes.
5803 -- The dereference is added either in Analyze_Call or here. Should
5804 -- be consolidated ???
5813 -- Check that a call to Current_Task does not occur in an entry body
5816 declare
5819 begin
5821 loop
5824 -- Exclude calls that occur within the default of a formal
5825 -- parameter of the entry, since those are evaluated outside
5826 -- of the body.
5833 then
5836 Error_Msg_NE
5850 -- Check that a procedure call does not occur in the context of the
5851 -- entry call statement of a conditional or timed entry call. Note that
5852 -- the case of a call to a subprogram renaming of an entry will also be
5853 -- rejected. The test for N not being an N_Entry_Call_Statement is
5854 -- defensive, covering the possibility that the processing of entry
5855 -- calls might reach this point due to later modifications of the code
5856 -- above.
5861 then
5865 -- Ada 2005 (AI-345): If a procedure_call_statement is used
5866 -- for a procedure_or_entry_call, the procedure_name or
5867 -- procedure_prefix of the procedure_call_statement shall denote
5868 -- an entry renamed by a procedure, or (a view of) a primitive
5869 -- subprogram of a limited interface whose first parameter is
5870 -- a controlling parameter.
5875 then
5876 Error_Msg_N
5881 -- If the SPARK_05 restriction is active, we are not allowed
5882 -- to have a call to a subprogram before we see its completion.
5887 -- Don't flag strange internal calls
5892 -- Only flag calls in extended main source
5897 -- Exclude enumeration literals from this processing
5900 then
5901 Check_SPARK_05_Restriction
5905 -- Check that this is not a call to a protected procedure or entry from
5906 -- within a protected function.
5910 -- Freeze the subprogram name if not in a spec-expression. Note that
5911 -- we freeze procedure calls as well as function calls. Procedure calls
5912 -- are not frozen according to the rules (RM 13.14(14)) because it is
5913 -- impossible to have a procedure call to a non-frozen procedure in
5914 -- pure Ada, but in the code that we generate in the expander, this
5915 -- rule needs extending because we can generate procedure calls that
5916 -- need freezing.
5918 -- In Ada 2012, expression functions may be called within pre/post
5919 -- conditions of subsequent functions or expression functions. Such
5920 -- calls do not freeze when they appear within generated bodies,
5921 -- (including the body of another expression function) which would
5922 -- place the freeze node in the wrong scope. An expression function
5923 -- is frozen in the usual fashion, by the appearance of a real body,
5924 -- or at the end of a declarative part.
5927 and then not In_Spec_Expression
5929 and then
5932 then
5936 -- For a predefined operator, the type of the result is the type imposed
5937 -- by context, except for a predefined operation on universal fixed.
5938 -- Otherwise The type of the call is the type returned by the subprogram
5939 -- being called.
5946 -- If the subprogram returns an array type, and the context requires the
5947 -- component type of that array type, the node is really an indexing of
5948 -- the parameterless call. Resolve as such. A pathological case occurs
5949 -- when the type of the component is an access to the array type. In
5950 -- this case the call is truly ambiguous.
5953 and then
5956 or else
5959 and then
5961 then
5962 declare
5967 begin
5970 then
5971 Error_Msg_N
5973 else
5976 -- The called entity may be an explicit dereference, in which
5977 -- case there is no entity to set.
5985 or else
5987 and then
5989 then
5992 -- Indexed call to a parameterless function
5994 Index_Node :=
5996 Prefix =>
5999 else
6000 -- An Ada 2005 prefixed call to a primitive operation
6001 -- whose first parameter is the prefix. This prefix was
6002 -- prepended to the parameter list, which is actually a
6003 -- list of indexes. Remove the prefix in order to build
6004 -- the proper indexed component.
6006 Index_Node :=
6008 Prefix =>
6011 Parameter_Associations =>
6012 New_List
6017 -- Preserve the parenthesis count of the node
6021 -- Since we are correcting a node classification error made
6022 -- by the parser, we call Replace rather than Rewrite.
6036 else
6037 -- If the function returns the limited view of type, the call must
6038 -- appear in a context in which the non-limited view is available.
6039 -- As is done in Try_Object_Operation, use the available view to
6040 -- prevent back-end confusion.
6049 -- In the case where the call is to an overloaded subprogram, Analyze
6050 -- calls Normalize_Actuals once per overloaded subprogram. Therefore in
6051 -- such a case Normalize_Actuals needs to be called once more to order
6052 -- the actuals correctly. Otherwise the call will have the ordering
6053 -- given by the last overloaded subprogram whether this is the correct
6054 -- one being called or not.
6061 -- In any case, call is fully resolved now. Reset Overload flag, to
6062 -- prevent subsequent overload resolution if node is analyzed again
6067 -- A Ghost entity must appear in a specific context
6073 -- If we are calling the current subprogram from immediately within its
6074 -- body, then that is the case where we can sometimes detect cases of
6075 -- infinite recursion statically. Do not try this in case restriction
6076 -- No_Recursion is in effect anyway, and do it only for source calls.
6081 -- Check violation of SPARK_05 restriction which does not permit
6082 -- a subprogram body to contain a call to the subprogram directly.
6086 then
6087 Check_SPARK_05_Restriction
6091 -- Issue warning for possible infinite recursion in the absence
6092 -- of the No_Recursion restriction.
6097 then
6098 -- Here we detected and flagged an infinite recursion, so we do
6099 -- not need to test the case below for further warnings. Also we
6100 -- are all done if we now have a raise SE node.
6106 -- If call is to immediately containing subprogram, then check for
6107 -- the case of a possible run-time detectable infinite recursion.
6109 else
6113 -- Although in general case, recursion is not statically
6114 -- checkable, the case of calling an immediately containing
6115 -- subprogram is easy to catch.
6119 -- If the recursive call is to a parameterless subprogram,
6120 -- then even if we can't statically detect infinite
6121 -- recursion, this is pretty suspicious, and we output a
6122 -- warning. Furthermore, we will try later to detect some
6123 -- cases here at run time by expanding checking code (see
6124 -- Detect_Infinite_Recursion in package Exp_Ch6).
6126 -- If the recursive call is within a handler, do not emit a
6127 -- warning, because this is a common idiom: loop until input
6128 -- is correct, catch illegal input in handler and restart.
6134 then
6135 -- For the case of a procedure call. We give the message
6136 -- only if the call is the first statement in a sequence
6137 -- of statements, or if all previous statements are
6138 -- simple assignments. This is simply a heuristic to
6139 -- decrease false positives, without losing too many good
6140 -- warnings. The idea is that these previous statements
6141 -- may affect global variables the procedure depends on.
6142 -- We also exclude raise statements, that may arise from
6143 -- constraint checks and are probably unrelated to the
6144 -- intended control flow.
6148 then
6149 declare
6151 begin
6155 N_Raise_Constraint_Error)
6156 then
6165 -- Do not give warning if we are in a conditional context
6167 declare
6169 begin
6175 then
6180 -- Here warning is to be issued
6196 -- Check obsolescent reference to Ada.Characters.Handling subprogram
6200 -- If subprogram name is a predefined operator, it was given in
6201 -- functional notation. Replace call node with operator node, so
6202 -- that actuals can be resolved appropriately.
6210 then
6216 -- Create a transient scope if the resulting type requires it
6218 -- There are several notable exceptions:
6220 -- a) In init procs, the transient scope overhead is not needed, and is
6221 -- even incorrect when the call is a nested initialization call for a
6222 -- component whose expansion may generate adjust calls. However, if the
6223 -- call is some other procedure call within an initialization procedure
6224 -- (for example a call to Create_Task in the init_proc of the task
6225 -- run-time record) a transient scope must be created around this call.
6227 -- b) Enumeration literal pseudo-calls need no transient scope
6229 -- c) Intrinsic subprograms (Unchecked_Conversion and source info
6230 -- functions) do not use the secondary stack even though the return
6231 -- type may be unconstrained.
6233 -- d) Calls to a build-in-place function, since such functions may
6234 -- allocate their result directly in a target object, and cases where
6235 -- the result does get allocated in the secondary stack are checked for
6236 -- within the specialized Exp_Ch6 procedures for expanding those
6237 -- build-in-place calls.
6239 -- e) If the subprogram is marked Inline_Always, then even if it returns
6240 -- an unconstrained type the call does not require use of the secondary
6241 -- stack. However, inlining will only take place if the body to inline
6242 -- is already present. It may not be available if e.g. the subprogram is
6243 -- declared in a child instance.
6245 -- If this is an initialization call for a type whose construction
6246 -- uses the secondary stack, and it is not a nested call to initialize
6247 -- a component, we do need to create a transient scope for it. We
6248 -- check for this by traversing the type in Check_Initialization_Call.
6254 then
6260 then
6263 elsif Expander_Active
6266 and then
6268 or else
6270 then
6273 -- If the call appears within the bounds of a loop, it will
6274 -- be rewritten and reanalyzed, nothing left to do here.
6281 and then not Within_Init_Proc
6282 then
6286 -- A protected function cannot be called within the definition of the
6287 -- enclosing protected type, unless it is part of a pre/postcondition
6288 -- on another protected operation.
6293 and then not In_Spec_Expression
6294 then
6295 Error_Msg_NE
6299 -- Propagate interpretation to actuals, and add default expressions
6300 -- where needed.
6305 -- Overloaded literals are rewritten as function calls, for purpose of
6306 -- resolution. After resolution, we can replace the call with the
6307 -- literal itself.
6313 -- Avoid validation, since it is a static function call
6319 -- If the subprogram is not global, then kill all saved values and
6320 -- checks. This is a bit conservative, since in many cases we could do
6321 -- better, but it is not worth the effort. Similarly, we kill constant
6322 -- values. However we do not need to do this for internal entities
6323 -- (unless they are inherited user-defined subprograms), since they
6324 -- are not in the business of molesting local values.
6326 -- If the flag Suppress_Value_Tracking_On_Calls is set, then we also
6327 -- kill all checks and values for calls to global subprograms. This
6328 -- takes care of the case where an access to a local subprogram is
6329 -- taken, and could be passed directly or indirectly and then called
6330 -- from almost any context.
6332 -- Note: we do not do this step till after resolving the actuals. That
6333 -- way we still take advantage of the current value information while
6334 -- scanning the actuals.
6336 -- We suppress killing values if we are processing the nodes associated
6337 -- with N_Freeze_Entity nodes. Otherwise the declaration of a tagged
6338 -- type kills all the values as part of analyzing the code that
6339 -- initializes the dispatch tables.
6343 or else Suppress_Value_Tracking_On_Call
6348 then
6349 Kill_Current_Values;
6352 -- If we are warning about unread OUT parameters, this is the place to
6353 -- set Last_Assignment for OUT and IN OUT parameters. We have to do this
6354 -- after the above call to Kill_Current_Values (since that call clears
6355 -- the Last_Assignment field of all local variables).
6360 then
6361 declare
6365 begin
6375 then
6385 -- If the subprogram is a primitive operation, check whether or not
6386 -- it is a correct dispatching call.
6390 then
6395 and then not In_Instance
6396 then
6400 -- If this is a dispatching call, generate the appropriate reference,
6401 -- for better source navigation in GPS.
6405 then
6408 -- Normal case, not a dispatching call: generate a call reference
6410 else
6418 -- Check for violation of restriction No_Specific_Termination_Handlers
6419 -- and warn on a potentially blocking call to Abort_Task.
6423 or else
6425 then
6432 -- A call to Ada.Real_Time.Timing_Events.Set_Handler to set a relative
6433 -- timing event violates restriction No_Relative_Delay (AI-0211). We
6434 -- need to check the second argument to determine whether it is an
6435 -- absolute or relative timing event.
6440 then
6444 -- Issue an error for a call to an eliminated subprogram. This routine
6445 -- will not perform the check if the call appears within a default
6446 -- expression.
6450 -- In formal mode, the primitive operations of a tagged type or type
6451 -- extension do not include functions that return the tagged type.
6457 then
6461 -- Implement rule in 12.5.1 (23.3/2): In an instance, if the actual is
6462 -- class-wide and the call dispatches on result in a context that does
6463 -- not provide a tag, the call raises Program_Error.
6466 and then In_Instance
6471 then
6472 -- Verify that none of the formals are controlling
6474 declare
6478 begin
6500 -- Check for calling a function with OUT or IN OUT parameter when the
6501 -- calling context (us right now) is not Ada 2012, so does not allow
6502 -- OUT or IN OUT parameters in function calls. Functions declared in
6503 -- a predefined unit are OK, as they may be called indirectly from a
6504 -- user-declared instantiation.
6510 then
6515 -- Check the dimensions of the actuals in the call. For function calls,
6516 -- propagate the dimensions from the returned type to N.
6520 -- All done, evaluate call and deal with elaboration issues
6525 -- In GNATprove mode, expansion is disabled, but we want to inline some
6526 -- subprograms to facilitate formal verification. Indirect calls through
6527 -- a subprogram type or within a generic cannot be inlined. Inlining is
6528 -- performed only for calls subject to SPARK_Mode on.
6530 if GNATprove_Mode
6533 and then not Inside_A_Generic
6534 then
6541 -- Nothing to do if the subprogram is not eligible for inlining in
6542 -- GNATprove mode.
6546 then
6549 -- Calls cannot be inlined inside assertions, as GNATprove treats
6550 -- assertions as logic expressions.
6553 Cannot_Inline
6556 -- Calls cannot be inlined inside default expressions
6559 Cannot_Inline
6562 -- Inlining should not be performed during pre-analysis
6566 -- With the one-pass inlining technique, a call cannot be
6567 -- inlined if the corresponding body has not been seen yet.
6570 Cannot_Inline
6573 -- Nothing to do if there is no body to inline, indicating that
6574 -- the subprogram is not suitable for inlining in GNATprove
6575 -- mode.
6580 -- Do not inline calls inside expression functions, as this
6581 -- would prevent interpreting them as logical formulas in
6582 -- GNATprove.
6585 and then
6587 then
6588 Cannot_Inline
6592 -- Calls cannot be inlined inside potentially unevaluated
6593 -- expressions, as this would create complex actions inside
6594 -- expressions, that are not handled by GNATprove.
6597 Cannot_Inline
6601 -- Otherwise, inline the call
6603 else
6613 -----------------------------
6614 -- Resolve_Case_Expression --
6615 -----------------------------
6623 begin
6630 -- When the expression is of a scalar subtype different from the
6631 -- result subtype, then insert a conversion to ensure the generation
6632 -- of a constraint check.
6642 -- Apply RM 4.5.7 (17/3): whether the expression is statically or
6643 -- dynamically tagged must be known statically.
6651 Error_Msg_N
6664 -------------------------------
6665 -- Resolve_Character_Literal --
6666 -------------------------------
6672 begin
6673 -- Verify that the character does belong to the type of the context
6678 -- Wide_Wide_Character literals must always be defined, since the set
6679 -- of wide wide character literals is complete, i.e. if a character
6680 -- literal is accepted by the parser, then it is OK for wide wide
6681 -- character (out of range character literals are rejected).
6686 -- Always accept character literal for type Any_Character, which
6687 -- occurs in error situations and in comparisons of literals, both
6688 -- of which should accept all literals.
6693 -- For Standard.Character or a type derived from it, check that the
6694 -- literal is in range.
6701 -- For Standard.Wide_Character or a type derived from it, check that the
6702 -- literal is in range.
6709 -- For Standard.Wide_Wide_Character or a type derived from it, we
6710 -- know the literal is in range, since the parser checked.
6715 -- If the entity is already set, this has already been resolved in a
6716 -- generic context, or comes from expansion. Nothing else to do.
6721 -- Otherwise we have a user defined character type, and we can use the
6722 -- standard visibility mechanisms to locate the referenced entity.
6724 else
6737 -- If we fall through, then the literal does not match any of the
6738 -- entries of the enumeration type. This isn't just a constraint error
6739 -- situation, it is an illegality (see RM 4.2).
6741 Error_Msg_NE
6745 ---------------------------
6746 -- Resolve_Comparison_Op --
6747 ---------------------------
6749 -- Context requires a boolean type, and plays no role in resolution.
6750 -- Processing identical to that for equality operators. The result type is
6751 -- the base type, which matters when pathological subtypes of booleans with
6752 -- limited ranges are used.
6759 begin
6760 -- If this is an intrinsic operation which is not predefined, use the
6761 -- types of its declared arguments to resolve the possibly overloaded
6762 -- operands. Otherwise the operands are unambiguous and specify the
6763 -- expected type.
6768 else
6779 -- Skip remaining processing if already set to Any_Type
6785 -- Deal with other error cases
6789 T = Any_Character
6790 then
6793 else
6801 -- Resolve the operands if types OK
6810 -- In SPARK, ordering operators <, <=, >, >= are not defined for Boolean
6811 -- types or array types except String.
6814 Check_SPARK_05_Restriction
6819 then
6820 Check_SPARK_05_Restriction
6824 -- Check comparison on unordered enumeration
6828 Error_Msg_NE
6833 -- Evaluate the relation (note we do this after the above check since
6834 -- this Eval call may change N to True/False.
6840 -----------------------------------------
6841 -- Resolve_Discrete_Subtype_Indication --
6842 -----------------------------------------
6844 procedure Resolve_Discrete_Subtype_Indication
6847 is
6851 begin
6859 else
6869 Error_Msg_NE
6872 -- Rewrite the constraint as a range of Typ
6873 -- to allow compilation to proceed further.
6885 else
6889 -- Additionally, we must check that the bounds are compatible
6890 -- with the given subtype, which might be different from the
6891 -- type of the context.
6895 -- ??? If the above check statically detects a Constraint_Error
6896 -- it replaces the offending bound(s) of the range R with a
6897 -- Constraint_Error node. When the itype which uses these bounds
6898 -- is frozen the resulting call to Duplicate_Subexpr generates
6899 -- a new temporary for the bounds.
6901 -- Unfortunately there are other itypes that are also made depend
6902 -- on these bounds, so when Duplicate_Subexpr is called they get
6903 -- a forward reference to the newly created temporaries and Gigi
6904 -- aborts on such forward references. This is probably sign of a
6905 -- more fundamental problem somewhere else in either the order of
6906 -- itype freezing or the way certain itypes are constructed.
6908 -- To get around this problem we call Remove_Side_Effects right
6909 -- away if either bounds of R are a Constraint_Error.
6911 declare
6915 begin
6931 -------------------------
6932 -- Resolve_Entity_Name --
6933 -------------------------
6935 -- Used to resolve identifiers and expanded names
6938 function Is_Assignment_Or_Object_Expression
6941 -- Determine whether node Context denotes an assignment statement or an
6942 -- object declaration whose expression is node Expr.
6944 ----------------------------------------
6945 -- Is_Assignment_Or_Object_Expression --
6946 ----------------------------------------
6948 function Is_Assignment_Or_Object_Expression
6951 is
6952 begin
6954 N_Object_Declaration)
6956 then
6959 -- Check whether a construct that yields a name is the expression of
6960 -- an assignment statement or an object declaration.
6963 N_Explicit_Dereference,
6964 N_Indexed_Component,
6965 N_Selected_Component,
6966 N_Slice)
6968 or else
6970 N_Unchecked_Type_Conversion)
6972 then
6973 return
6974 Is_Assignment_Or_Object_Expression
6978 -- Otherwise the context is not an assignment statement or an object
6979 -- declaration.
6981 else
6986 -- Local variables
6991 -- Start of processing for Resolve_Entity_Name
6993 begin
6994 -- If garbage from errors, set to Any_Type and return
7001 -- Replace named numbers by corresponding literals. Note that this is
7002 -- the one case where Resolve_Entity_Name must reset the Etype, since
7003 -- it is currently marked as universal.
7013 -- For enumeration literals, we need to make sure that a proper style
7014 -- check is done, since such literals are overloaded, and thus we did
7015 -- not do a style check during the first phase of analysis.
7021 -- Case of (sub)type name appearing in a context where an expression
7022 -- is expected. This is legal if occurrence is a current instance.
7023 -- See RM 8.6 (17/3).
7029 -- Any other use is an error
7031 else
7032 Error_Msg_N
7036 -- Check discriminant use if entity is discriminant in current scope,
7037 -- i.e. discriminant of record or concurrent type currently being
7038 -- analyzed. Uses in corresponding body are unrestricted.
7043 then
7046 -- A parameterless generic function cannot appear in a context that
7047 -- requires resolution.
7052 -- In Ada 83 an OUT parameter cannot be read
7057 or else Is_Assignment_Or_Object_Expression
7060 then
7065 -- In all other cases, just do the possible static evaluation
7067 else
7068 -- A deferred constant that appears in an expression must have a
7069 -- completion, unless it has been removed by in-place expansion of
7070 -- an aggregate. A constant that is a renaming does not need
7071 -- initialization.
7077 and then not In_Spec_Expression
7080 then
7084 then
7086 else
7087 Error_Msg_N
7097 -- When the entity appears in a parameter association, retrieve the
7098 -- related subprogram call.
7106 -- The following checks are only relevant when SPARK_Mode is on as
7107 -- they are not standard Ada legality rules.
7111 -- An effectively volatile object subject to enabled properties
7112 -- Async_Writers or Effective_Reads must appear in non-interfering
7113 -- context (SPARK RM 7.1.3(12)).
7120 then
7121 SPARK_Msg_N
7126 -- Check for possible elaboration issues with respect to reads of
7127 -- variables. The act of renaming the variable is not considered a
7128 -- read as it simply establishes an alias.
7131 and then Dynamic_Elaboration_Checks
7133 then
7137 -- The variable may eventually become a constituent of a single
7138 -- protected/task type. Record the reference now and verify its
7139 -- legality when analyzing the contract of the variable
7140 -- (SPARK RM 9.3).
7147 -- A Ghost entity must appear in a specific context
7155 -------------------
7156 -- Resolve_Entry --
7157 -------------------
7169 -- If the bounds of the entry family being called depend on task
7170 -- discriminants, build a new index subtype where a discriminant is
7171 -- replaced with the value of the discriminant of the target task.
7172 -- The target task is the prefix of the entry name in the call.
7174 -----------------------
7175 -- Actual_Index_Type --
7176 -----------------------
7186 -- If the bound is given by a discriminant, replace with a reference
7187 -- to the discriminant of the same name in the target task. If the
7188 -- entry name is the target of a requeue statement and the entry is
7189 -- in the current protected object, the bound to be used is the
7190 -- discriminal of the object (see Apply_Range_Checks for details of
7191 -- the transformation).
7193 -----------------------------
7194 -- Actual_Discriminant_Ref --
7195 -----------------------------
7201 begin
7206 then
7212 then
7213 -- Note: here Bound denotes a discriminant of the corresponding
7214 -- record type tskV, whose discriminal is a formal of the
7215 -- init-proc tskVIP. What we want is the body discriminal,
7216 -- which is associated to the discriminant of the original
7217 -- concurrent type tsk.
7219 return New_Occurrence_Of
7222 else
7223 Ref :=
7233 -- Start of processing for Actual_Index_Type
7235 begin
7238 then
7241 else
7255 -- Start of processing for Resolve_Entry
7257 begin
7258 -- Find name of entry being called, and resolve prefix of name with its
7259 -- own type. The prefix can be overloaded, and the name and signature of
7260 -- the entry must be taken into account.
7264 -- Case of dealing with entry family within the current tasks
7268 else
7274 -- Entry call to an entry (or entry family) in the current task. This
7275 -- is legal even though the task will deadlock. Rewrite as call to
7276 -- current task.
7278 -- This can also be a call to an entry in an enclosing task. If this
7279 -- is a single task, we have to retrieve its name, because the scope
7280 -- of the entry is the task type, not the object. If the enclosing
7281 -- task is a task type, the identity of the task is given by its own
7282 -- self variable.
7284 -- Finally this can be a requeue on an entry of the same task or
7285 -- protected object.
7292 then
7293 -- S is an enclosing task or protected object. The concurrent
7294 -- declaration has been converted into a type declaration, and
7295 -- the object itself has an object declaration that follows
7296 -- the type in the same declarative part.
7308 -- Call to current task. Will be transformed into call to Self
7315 New_N :=
7318 Selector_Name =>
7325 then
7326 -- Use the entry name (which must be unique at this point) to find
7327 -- the prefix that returns the corresponding task/protected type.
7329 declare
7335 begin
7357 -- Up to this point the expression could have been the actual in a
7358 -- simple entry call, and be given by a named association.
7362 else
7368 ------------------------
7369 -- Resolve_Entry_Call --
7370 ------------------------
7382 begin
7383 -- We kill all checks here, because it does not seem worth the effort to
7384 -- do anything better, an entry call is a big operation.
7386 Kill_All_Checks;
7388 -- Processing of the name is similar for entry calls and protected
7389 -- operation calls. Once the entity is determined, we can complete
7390 -- the resolution of the actuals.
7392 -- The selector may be overloaded, in the case of a protected object
7393 -- with overloaded functions. The type of the context is used for
7394 -- resolution.
7399 then
7400 declare
7404 begin
7423 -- Simple entry call
7431 -- Call to member of entry family
7438 -- We cannot in general check the maximum depth of protected entry calls
7439 -- at compile time. But we can tell that any protected entry call at all
7440 -- violates a specified nesting depth of zero.
7446 -- Use context type to disambiguate a protected function that can be
7447 -- called without actuals and that returns an array type, and where the
7448 -- argument list may be an indexing of the returned value.
7453 and then
7459 and then
7460 Covers
7463 then
7464 declare
7467 begin
7468 Index_Node :=
7470 Prefix =>
7474 -- Since we are correcting a node classification error made by the
7475 -- parser, we call Replace rather than Rewrite.
7488 then
7490 -- Note the entity being called before rewriting the call, so that
7491 -- it appears used at this point.
7495 -- Rewrite as call to the precondition wrapper, adding the task
7496 -- object to the list of actuals. If the call is to a member of an
7497 -- entry family, include the index as well.
7499 declare
7503 begin
7512 New_Call :=
7514 Name =>
7519 -- Preanalyze and resolve new call. Current procedure is called
7520 -- from Resolve_Call, after which expansion will take place.
7527 -- The operation name may have been overloaded. Order the actuals
7528 -- according to the formals of the resolved entity, and set the return
7529 -- type to that of the operation.
7536 -- Reset the Is_Overloaded flag, since resolution is now completed
7538 -- Simple entry call
7543 -- Call to a member of an entry family
7553 -- Create a call reference to the entry
7561 -- Verify that a procedure call cannot masquerade as an entry
7562 -- call where an entry call is expected.
7567 then
7572 then
7577 then
7582 -- After resolution, entry calls and protected procedure calls are
7583 -- changed into entry calls, for expansion. The structure of the node
7584 -- does not change, so it can safely be done in place. Protected
7585 -- function calls must keep their structure because they are
7586 -- subexpressions.
7590 -- A protected operation that is not a function may modify the
7591 -- corresponding object, and cannot apply to a constant. If this
7592 -- is an internal call, the prefix is the type itself.
7598 then
7599 Error_Msg_N
7601 Entry_Name);
7615 -- Protected functions can return on the secondary stack, in which
7616 -- case we must trigger the transient scope mechanism.
7618 elsif Expander_Active
7620 then
7625 -------------------------
7626 -- Resolve_Equality_Op --
7627 -------------------------
7629 -- Both arguments must have the same type, and the boolean context does
7630 -- not participate in the resolution. The first pass verifies that the
7631 -- interpretation is not ambiguous, and the type of the left argument is
7632 -- correctly set, or is Any_Type in case of ambiguity. If both arguments
7633 -- are strings or aggregates, allocators, or Null, they are ambiguous even
7634 -- though they carry a single (universal) type. Diagnose this case here.
7642 -- The resolution rule for if expressions requires that each such must
7643 -- have a unique type. This means that if several dependent expressions
7644 -- are of a non-null anonymous access type, and the context does not
7645 -- impose an expected type (as can be the case in an equality operation)
7646 -- the expression must be rejected.
7649 -- Attempt to explain the nature of a redundant comparison with True. If
7650 -- the expression N is too complex, this routine issues a general error
7651 -- message.
7654 -- In the case of allocators and access attributes, the context must
7655 -- provide an indication of the specific access type to be used. If
7656 -- one operand is of such a "generic" access type, check whether there
7657 -- is a specific visible access type that has the same designated type.
7658 -- This is semantically dubious, and of no interest to any real code,
7659 -- but c48008a makes it all worthwhile.
7661 -------------------------
7662 -- Check_If_Expression --
7663 -------------------------
7669 begin
7676 then
7682 ------------------------
7683 -- Explain_Redundancy --
7684 ------------------------
7691 begin
7694 -- Strip the operand down to an entity
7696 loop
7699 else
7704 -- The construct denotes an entity
7709 -- Do not generate an error message when the comparison is done
7710 -- against the enumeration literal Standard.True.
7714 -- Build a customized error message
7741 -- The construct is too complex to disect, issue a general message
7743 else
7748 -----------------------------
7749 -- Find_Unique_Access_Type --
7750 -----------------------------
7757 begin
7759 E_Access_Attribute_Type)
7760 then
7764 E_Access_Attribute_Type)
7765 then
7767 else
7779 then
7792 -- Start of processing for Resolve_Equality_Op
7794 begin
7805 T = Any_Character
7806 then
7809 else
7818 then
7827 -- If expressions must have a single type, and if the context does
7828 -- not impose one the dependent expressions cannot be anonymous
7829 -- access types.
7831 -- Why no similar processing for case expressions???
7835 E_Anonymous_Access_Subprogram_Type)
7837 E_Anonymous_Access_Subprogram_Type)
7838 then
7846 -- In SPARK, equality operators = and /= for array types other than
7847 -- String are only defined when, for each index position, the
7848 -- operands have equal static bounds.
7852 -- Protect call to Matching_Static_Array_Bounds to avoid costly
7853 -- operation if not needed.
7861 then
7862 Check_SPARK_05_Restriction
7867 -- If the unique type is a class-wide type then it will be expanded
7868 -- into a dispatching call to the predefined primitive. Therefore we
7869 -- check here for potential violation of such restriction.
7875 if Warn_On_Redundant_Constructs
7880 then
7881 Error_Msg_N -- CODEFIX
7891 -- If this is an inequality, it may be the implicit inequality
7892 -- created for a user-defined operation, in which case the corres-
7893 -- ponding equality operation is not intrinsic, and the operation
7894 -- cannot be constant-folded. Else fold.
7899 or else Is_Intrinsic_Subprogram
7901 then
7907 then
7911 -- Ada 2005: If one operand is an anonymous access type, convert the
7912 -- other operand to it, to ensure that the underlying types match in
7913 -- the back-end. Same for access_to_subprogram, and the conversion
7914 -- verifies that the types are subtype conformant.
7916 -- We apply the same conversion in the case one of the operands is a
7917 -- private subtype of the type of the other.
7919 -- Why the Expander_Active test here ???
7921 if Expander_Active
7922 and then
7924 E_Anonymous_Access_Subprogram_Type)
7926 then
7946 ----------------------------------
7947 -- Resolve_Explicit_Dereference --
7948 ----------------------------------
7956 -- The candidate prefix type, if overloaded
7961 begin
7965 -- A useful optimization: check whether the dereference denotes an
7966 -- element of a container, and if so rewrite it as a call to the
7967 -- corresponding Element function.
7969 -- Disabled for now, on advice of ARG. A more restricted form of the
7970 -- predicate might be acceptable ???
7972 -- if Is_Container_Element (N) then
7973 -- return;
7974 -- end if;
7978 -- Use the context type to select the prefix that has the correct
7979 -- designated type. Keep the first match, which will be the inner-
7980 -- most.
7987 then
7992 -- Remove access types that do not match, but preserve access
7993 -- to subprogram interpretations, in case a further dereference
7994 -- is needed (see below).
8007 else
8008 -- If no interpretation covers the designated type of the prefix,
8009 -- this is the pathological case where not all implementations of
8010 -- the prefix allow the interpretation of the node as a call. Now
8011 -- that the expected type is known, Remove other interpretations
8012 -- from prefix, rewrite it as a call, and resolve again, so that
8013 -- the proper call node is generated.
8024 New_N :=
8026 Name =>
8037 -- If not overloaded, resolve P with its own type
8039 else
8043 -- If the prefix might be null, add an access check
8047 then
8051 -- If the designated type is a packed unconstrained array type, and the
8052 -- explicit dereference is not in the context of an attribute reference,
8053 -- then we must compute and set the actual subtype, since it is needed
8054 -- by Gigi. The reason we exclude the attribute case is that this is
8055 -- handled fine by Gigi, and in fact we use such attributes to build the
8056 -- actual subtype. We also exclude generated code (which builds actual
8057 -- subtypes directly if they are needed).
8064 then
8070 -- Note: No Eval processing is required for an explicit dereference,
8071 -- because such a name can never be static.
8075 -------------------------------------
8076 -- Resolve_Expression_With_Actions --
8077 -------------------------------------
8080 begin
8083 -- If N has no actions, and its expression has been constant folded,
8084 -- then rewrite N as just its expression. Note, we can't do this in
8085 -- the general case of Is_Empty_List (Actions (N)) as this would cause
8086 -- Expression (N) to be expanded again.
8090 then
8095 ----------------------------------
8096 -- Resolve_Generalized_Indexing --
8097 ----------------------------------
8105 begin
8106 -- In ASIS mode, propagate the information about the indexes back to
8107 -- to the original indexing node. The generalized indexing is either
8108 -- a function call, or a dereference of one. The actuals include the
8109 -- prefix of the original node, which is the container expression.
8118 loop
8127 -- If expression is to be reanalyzed, reset Generalized_Indexing
8128 -- to recreate call node, as is the case when the expression is
8129 -- part of an expression function.
8138 else
8144 ---------------------------
8145 -- Resolve_If_Expression --
8146 ---------------------------
8155 begin
8160 -- When the "then" expression is of a scalar subtype different from the
8161 -- result subtype, then insert a conversion to ensure the generation of
8162 -- a constraint check. The same is done for the else part below, again
8163 -- comparing subtypes rather than base types.
8167 then
8172 -- If ELSE expression present, just resolve using the determined type
8173 -- If type is universal, resolve to any member of the class.
8182 else
8192 -- Apply RM 4.5.7 (17/3): whether the expression is statically or
8193 -- dynamically tagged must be known statically.
8198 then
8204 -- If no ELSE expression is present, root type must be Standard.Boolean
8205 -- and we provide a Standard.True result converted to the appropriate
8206 -- Boolean type (in case it is a derived boolean type).
8209 Else_Expr :=
8214 else
8223 -------------------------------
8224 -- Resolve_Indexed_Component --
8225 -------------------------------
8233 begin
8241 -- Use the context type to select the prefix that yields the correct
8242 -- component type.
8244 declare
8251 begin
8258 and then
8259 Covers
8262 then
8271 else
8277 else
8288 else
8295 -- If prefix is access type, dereference to get real array type.
8296 -- Note: we do not apply an access check because the expander always
8297 -- introduces an explicit dereference, and the check will happen there.
8303 -- If name was overloaded, set component type correctly now
8304 -- If a misplaced call to an entry family (which has no index types)
8305 -- return. Error will be diagnosed from calling context.
8309 else
8316 -- The prefix may have resolved to a string literal, in which case its
8317 -- etype has a special representation. This is only possible currently
8318 -- if the prefix is a static concatenation, written in functional
8319 -- notation.
8324 else
8331 else
8342 -- Do not generate the warning on suspicious index if we are analyzing
8343 -- package Ada.Tags; otherwise we will report the warning with the
8344 -- Prims_Ptr field of the dispatch table.
8347 or else not
8349 Ada_Tags)
8350 then
8355 -- If the array type is atomic, and the component is not atomic, then
8356 -- this is worth a warning, since we have a situation where the access
8357 -- to the component may cause extra read/writes of the atomic array
8358 -- object, or partial word accesses, which could be unexpected.
8364 and then Has_Atomic_Components
8367 then
8368 Error_Msg_N
8370 Error_Msg_N
8375 -----------------------------
8376 -- Resolve_Integer_Literal --
8377 -----------------------------
8380 begin
8385 --------------------------------
8386 -- Resolve_Intrinsic_Operator --
8387 --------------------------------
8396 -- If the operand is a literal, it cannot be the expression in a
8397 -- conversion. Use a qualified expression instead.
8399 ---------------------
8400 -- Convert_Operand --
8401 ---------------------
8407 begin
8409 Res :=
8415 else
8422 -- Start of processing for Resolve_Intrinsic_Operator
8424 begin
8425 -- We must preserve the original entity in a generic setting, so that
8426 -- the legality of the operation can be verified in an instance.
8441 -- If the result or operand types are private, rewrite with unchecked
8442 -- conversions on the operands and the result, to expose the proper
8443 -- underlying numeric type.
8448 then
8453 else
8474 then
8475 -- Add explicit conversion where needed, and save interpretations in
8476 -- case operands are overloaded.
8483 else
8489 else
8499 else
8504 --------------------------------------
8505 -- Resolve_Intrinsic_Unary_Operator --
8506 --------------------------------------
8508 procedure Resolve_Intrinsic_Unary_Operator
8511 is
8516 begin
8535 else
8540 ------------------------
8541 -- Resolve_Logical_Op --
8542 ------------------------
8547 begin
8550 -- Predefined operations on scalar types yield the base type. On the
8551 -- other hand, logical operations on arrays yield the type of the
8552 -- arguments (and the context).
8556 else
8560 -- The following test is required because the operands of the operation
8561 -- may be literals, in which case the resulting type appears to be
8562 -- compatible with a signed integer type, when in fact it is compatible
8563 -- only with modular types. If the context itself is universal, the
8564 -- operation is illegal.
8572 Error_Msg_N
8580 then
8584 -- Replace AND by AND THEN, or OR by OR ELSE, if Short_Circuit_And_Or
8585 -- is active and the result type is standard Boolean (do not mess with
8586 -- ops that return a nonstandard Boolean type, because something strange
8587 -- is going on).
8589 -- Note: you might expect this replacement to be done during expansion,
8590 -- but that doesn't work, because when the pragma Short_Circuit_And_Or
8591 -- is used, no part of the right operand of an "and" or "or" operator
8592 -- should be executed if the left operand would short-circuit the
8593 -- evaluation of the corresponding "and then" or "or else". If we left
8594 -- the replacement to expansion time, then run-time checks associated
8595 -- with such operands would be evaluated unconditionally, due to being
8596 -- before the condition prior to the rewriting as short-circuit forms
8597 -- during expansion.
8599 if Short_Circuit_And_Or
8602 then
8603 -- Mark the corresponding putative SCO operator as truly a logical
8604 -- (and short-circuit) operator.
8617 -- Case of OR changed to OR ELSE
8619 else
8627 -- Return now, since analysis of the rewritten ops will take care of
8628 -- other reference bookkeeping and expression folding.
8643 -- In SPARK, logical operations AND, OR and XOR for arrays are defined
8644 -- only when both operands have same static lower and higher bounds. Of
8645 -- course the types have to match, so only check if operands are
8646 -- compatible and the node itself has no errors.
8650 then
8651 declare
8655 begin
8656 -- Protect call to Matching_Static_Array_Bounds to avoid costly
8657 -- operation if not needed.
8664 then
8665 Check_SPARK_05_Restriction
8672 ---------------------------
8673 -- Resolve_Membership_Op --
8674 ---------------------------
8676 -- The context can only be a boolean type, and does not determine the
8677 -- arguments. Arguments should be unambiguous, but the preference rule for
8678 -- universal types applies.
8688 -- Analysis has determined a unique type for the left operand. Use it to
8689 -- resolve the disjuncts.
8691 ----------------------------
8692 -- Resolve_Set_Membership --
8693 ----------------------------
8699 begin
8700 -- If the left operand is overloaded, find type compatible with not
8701 -- overloaded alternative of the right operand.
8710 else
8715 -- Unclear how to resolve expression if all alternatives are also
8716 -- overloaded.
8722 else
8731 -- Alternative is an expression, a range
8732 -- or a subtype mark.
8736 then
8743 -- Check for duplicates for discrete case
8746 declare
8755 begin
8756 -- Loop checking duplicates. This is quadratic, but giant sets
8757 -- are unlikely in this context so it's a reasonable choice.
8764 N_Character_Literal)
8766 then
8784 -- Start of processing for Resolve_Membership_Op
8786 begin
8792 Resolve_Set_Membership;
8796 and then
8798 or else
8801 then
8804 -- Ada 2005 (AI-251): Support the following case:
8806 -- type I is interface;
8807 -- type T is tagged ...
8809 -- function Test (O : I'Class) is
8810 -- begin
8811 -- return O in T'Class.
8812 -- end Test;
8814 -- In this case we have nothing else to do. The membership test will be
8815 -- done at run time.
8822 then
8824 else
8828 -- If mixed-mode operations are present and operands are all literal,
8829 -- the only interpretation involves Duration, which is probably not
8830 -- the intention of the programmer.
8845 then
8851 else
8856 -- Here after resolving membership operation
8863 ------------------
8864 -- Resolve_Null --
8865 ------------------
8870 begin
8871 -- Handle restriction against anonymous null access values This
8872 -- restriction can be turned off using -gnatdj.
8874 -- Ada 2005 (AI-231): Remove restriction
8877 and then not Debug_Flag_J
8880 then
8881 -- In the common case of a call which uses an explicitly null value
8882 -- for an access parameter, give specialized error message.
8885 Error_Msg_N
8888 -- Standard message for all other cases (are there any?)
8890 else
8891 Error_Msg_N
8896 -- Ada 2005 (AI-231): Generate the null-excluding check in case of
8897 -- assignment to a null-excluding object
8902 then
8904 Insert_Action
8909 else
8916 -- In a distributed context, null for a remote access to subprogram may
8917 -- need to be replaced with a special record aggregate. In this case,
8918 -- return after having done the transformation.
8923 then
8927 -- The null literal takes its type from the context
8932 -----------------------
8933 -- Resolve_Op_Concat --
8934 -----------------------
8938 -- We wish to avoid deep recursion, because concatenations are often
8939 -- deeply nested, as in A&B&...&Z. Therefore, we walk down the left
8940 -- operands nonrecursively until we find something that is not a simple
8941 -- concatenation (A in this case). We resolve that, and then walk back
8942 -- up the tree following Parent pointers, calling Resolve_Op_Concat_Rest
8943 -- to do the rest of the work at each level. The Parent pointers allow
8944 -- us to avoid recursion, and thus avoid running out of memory. See also
8945 -- Sem_Ch4.Analyze_Concatenation, where a similar approach is used.
8950 begin
8951 -- The following code is equivalent to:
8953 -- Resolve_Op_Concat_First (NN, Typ);
8954 -- Resolve_Op_Concat_Arg (N, ...);
8955 -- Resolve_Op_Concat_Rest (N, Typ);
8957 -- where the Resolve_Op_Concat_Arg call recurses back here if the left
8958 -- operand is a concatenation.
8960 -- Walk down left operands
8962 loop
8971 -- Now (given the above example) NN is A&B and Op1 is A
8973 -- First resolve Op1 ...
8977 -- ... then walk NN back up until we reach N (where we started), calling
8978 -- Resolve_Op_Concat_Rest along the way.
8980 loop
8987 Check_SPARK_05_Restriction
8992 ---------------------------
8993 -- Resolve_Op_Concat_Arg --
8994 ---------------------------
8996 procedure Resolve_Op_Concat_Arg
9001 is
9005 begin
9007 if Is_Comp
9011 then
9013 else
9017 -- If both Array & Array and Array & Component are visible, there is a
9018 -- potential ambiguity that must be reported.
9023 then
9027 -- If the operation is user-defined and not overloaded use its
9028 -- profile. The operation may be a renaming, in which case it has
9029 -- been rewritten, and we want the original profile.
9034 then
9036 Etype
9040 -- Otherwise an aggregate may match both the array type and the
9041 -- component type.
9043 else
9048 else
9052 then
9053 declare
9058 begin
9063 -- Special-case the error message when the overloading is
9064 -- caused by a function that yields an array and can be
9065 -- called without parameters.
9070 Error_Msg_NE
9072 Error_Msg_NE
9076 else
9084 or else
9086 then
9087 Error_Msg_N -- CODEFIX
9105 else
9110 else
9114 -- Concatenation is restricted in SPARK: each operand must be either a
9115 -- string literal, the name of a string constant, a static character or
9116 -- string expression, or another concatenation. Arg cannot be a
9117 -- concatenation here as callers of Resolve_Op_Concat_Arg call it
9118 -- separately on each final operand, past concatenation operations.
9122 Check_SPARK_05_Restriction
9130 then
9131 Check_SPARK_05_Restriction
9135 -- Do not issue error on an operand that is neither a character nor a
9136 -- string, as the error is issued in Resolve_Op_Concat.
9138 else
9145 -----------------------------
9146 -- Resolve_Op_Concat_First --
9147 -----------------------------
9154 begin
9155 -- The parser folds an enormous sequence of concatenations of string
9156 -- literals into "" & "...", where the Is_Folded_In_Parser flag is set
9157 -- in the right operand. If the expression resolves to a predefined "&"
9158 -- operator, all is well. Otherwise, the parser's folding is wrong, so
9159 -- we give an error. See P_Simple_Expression in Par.Ch4.
9164 then
9179 ----------------------------
9180 -- Resolve_Op_Concat_Rest --
9181 ----------------------------
9187 begin
9196 -- If this is not a static concatenation, but the result is a string
9197 -- type (and not an array of strings) ensure that static string operands
9198 -- have their subtypes properly constructed.
9202 then
9208 ----------------------
9209 -- Resolve_Op_Expon --
9210 ----------------------
9215 begin
9216 -- Catch attempts to do fixed-point exponentiation with universal
9217 -- operands, which is a case where the illegality is not caught during
9218 -- normal operator analysis. This is not done in preanalysis mode
9219 -- since the tree is not fully decorated during preanalysis.
9230 then
9240 then
9247 then
9251 -- We do the resolution using the base type, because intermediate values
9252 -- in expressions are always of the base type, not a subtype of it.
9257 -- For integer types, right argument must be in Natural range
9272 -- Evaluate the exponentiation operator for dimensioned type
9275 else
9279 -- Set overflow checking bit. Much cleverer code needed here eventually
9280 -- and perhaps the Resolve routines should be separated for the various
9281 -- arithmetic operations, since they will need different processing. ???
9290 --------------------
9291 -- Resolve_Op_Not --
9292 --------------------
9298 -- This function determines if the parent node is a boolean operator or
9299 -- operation (comparison op, membership test, or short circuit form) and
9300 -- the not in question is the left operand of this operation. Note that
9301 -- if the not is in parens, then false is returned.
9303 -----------------------
9304 -- Parent_Is_Boolean --
9305 -----------------------
9308 begin
9312 else
9314 when N_Op_And |
9315 N_Op_Eq |
9316 N_Op_Ge |
9317 N_Op_Gt |
9318 N_Op_Le |
9319 N_Op_Lt |
9320 N_Op_Ne |
9321 N_Op_Or |
9322 N_Op_Xor |
9323 N_In |
9324 N_Not_In |
9325 N_And_Then |
9326 N_Or_Else =>
9336 -- Start of processing for Resolve_Op_Not
9338 begin
9339 -- Predefined operations on scalar types yield the base type. On the
9340 -- other hand, logical operations on arrays yield the type of the
9341 -- arguments (and the context).
9345 else
9349 -- Straightforward case of incorrect arguments
9356 -- Special case of probable missing parens
9360 Error_Msg_N
9363 else
9364 Error_Msg_N
9371 -- OK resolution of NOT
9373 else
9374 -- Warn if non-boolean types involved. This is a case like not a < b
9375 -- where a and b are modular, where we will get (not a) < b and most
9376 -- likely not (a < b) was intended.
9378 if Warn_On_Questionable_Missing_Parens
9380 and then Parent_Is_Boolean
9381 then
9385 -- Warn on double negation if checking redundant constructs
9387 if Warn_On_Redundant_Constructs
9392 then
9396 -- Complete resolution and evaluation of NOT
9406 -----------------------------
9407 -- Resolve_Operator_Symbol --
9408 -----------------------------
9410 -- Nothing to be done, all resolved already
9416 begin
9420 ----------------------------------
9421 -- Resolve_Qualified_Expression --
9422 ----------------------------------
9430 begin
9433 -- Protect call to Matching_Static_Array_Bounds to avoid costly
9434 -- operation if not needed.
9441 then
9442 Check_SPARK_05_Restriction
9446 -- A qualified expression requires an exact match of the type, class-
9447 -- wide matching is not allowed. However, if the qualifying type is
9448 -- specific and the expression has a class-wide type, it may still be
9449 -- okay, since it can be the result of the expansion of a call to a
9450 -- dispatching function, so we also have to check class-wideness of the
9451 -- type of the expression's original node.
9454 or else
9458 then
9462 -- If the target type is unconstrained, then we reset the type of the
9463 -- result from the type of the expression. For other cases, the actual
9464 -- subtype of the expression is the target type.
9468 then
9475 -- If we still have a qualified expression after the static evaluation,
9476 -- then apply a scalar range check if needed. The reason that we do this
9477 -- after the Eval call is that otherwise, the application of the range
9478 -- check may convert an illegal static expression and result in warning
9479 -- rather than giving an error (e.g Integer'(Integer'Last + 1)).
9485 -- Finally, check whether a predicate applies to the target type. This
9486 -- comes from AI12-0100. As for type conversions, check the enclosing
9487 -- context to prevent an infinite expansion.
9493 or else
9495 then
9498 -- In the case of a qualified expression in an allocator, the check
9499 -- is applied when expanding the allocator, so avoid redundant check.
9503 then
9509 ------------------------------
9510 -- Resolve_Raise_Expression --
9511 ------------------------------
9514 begin
9518 else
9523 -------------------
9524 -- Resolve_Range --
9525 -------------------
9532 -- Returns True if N is of the form X'First .. X'Last where X is the
9533 -- same entity for both attributes.
9535 --------------------
9536 -- First_Last_Ref --
9537 --------------------
9543 begin
9548 then
9549 declare
9552 begin
9556 then
9565 -- Start of processing for Resolve_Range
9567 begin
9572 -- Check for inappropriate range on unordered enumeration type
9576 -- Exclude X'First .. X'Last if X is the same entity for both
9578 and then not First_Last_Ref
9579 then
9581 Error_Msg_NE
9588 -- We have to check the bounds for being within the base range as
9589 -- required for a non-static context. Normally this is automatic and
9590 -- done as part of evaluating expressions, but the N_Range node is an
9591 -- exception, since in GNAT we consider this node to be a subexpression,
9592 -- even though in Ada it is not. The circuit in Sem_Eval could check for
9593 -- this, but that would put the test on the main evaluation path for
9594 -- expressions.
9599 -- Check for an ambiguous range over character literals. This will
9600 -- happen with a membership test involving only literals.
9608 -- If bounds are static, constant-fold them, so size computations are
9609 -- identical between front-end and back-end. Do not perform this
9610 -- transformation while analyzing generic units, as type information
9611 -- would be lost when reanalyzing the constant node in the instance.
9624 --------------------------
9625 -- Resolve_Real_Literal --
9626 --------------------------
9631 begin
9632 -- Special processing for fixed-point literals to make sure that the
9633 -- value is an exact multiple of small where this is required. We skip
9634 -- this for the universal real case, and also for generic types.
9640 then
9641 declare
9648 begin
9649 -- Case of literal is not an exact multiple of the Small
9653 -- For a source program literal for a decimal fixed-point type,
9654 -- this is statically illegal (RM 4.9(36)).
9659 then
9663 -- Generate a warning if literal from source
9666 and then Warn_On_Bad_Fixed_Value
9667 then
9668 Error_Msg_N
9670 N);
9673 -- Replace literal by a value that is the exact representation
9674 -- of a value of the type, i.e. a multiple of the small value,
9675 -- by truncation, since Machine_Rounds is false for all GNAT
9676 -- fixed-point types (RM 4.9(38)).
9686 -- In all cases, set the corresponding integer field
9692 -- Now replace the actual type by the expected type as usual
9698 -----------------------
9699 -- Resolve_Reference --
9700 -----------------------
9705 begin
9706 -- Replace general access with specific type
9714 -- If we are taking the reference of a volatile entity, then treat it as
9715 -- a potential modification of this entity. This is too conservative,
9716 -- but necessary because remove side effects can cause transformations
9717 -- of normal assignments into reference sequences that otherwise fail to
9718 -- notice the modification.
9725 --------------------------------
9726 -- Resolve_Selected_Component --
9727 --------------------------------
9742 -- Check whether this is the initialization of a component within an
9743 -- init proc (by assignment or call to another init proc). If true,
9744 -- there is no need for a discriminant check.
9746 --------------------
9747 -- Init_Component --
9748 --------------------
9751 begin
9752 return Inside_Init_Proc
9758 -- Start of processing for Resolve_Selected_Component
9760 begin
9763 -- Use the context type to select the prefix that has a selector
9764 -- of the correct name and type.
9772 else
9776 -- Locate selected component. For a private prefix the selector
9777 -- can denote a discriminant.
9781 -- The visible components of a class-wide type are those of
9782 -- the root type.
9792 then
9799 else
9803 Error_Msg_N
9808 else
9811 -- There may be an implicit dereference. Retrieve
9812 -- designated record type.
9816 else
9822 -- Resolution chooses the new interpretation.
9823 -- Find the component with the right name.
9828 loop
9845 -- There must be a legal interpretation at this point
9852 else
9853 -- Resolve prefix with its type
9858 -- Generate cross-reference. We needed to wait until full overloading
9859 -- resolution was complete to do this, since otherwise we can't tell if
9860 -- we are an lvalue or not.
9864 else
9868 -- If prefix is an access type, the node will be transformed into an
9869 -- explicit dereference during expansion. The type of the node is the
9870 -- designated type of that of the prefix.
9875 else
9879 -- Set flag for expander if discriminant check required on a component
9880 -- appearing within a variant.
9886 and then
9889 and then not Init_Component
9890 then
9898 -- If the prefix is a record conversion, this may be a renamed
9899 -- discriminant whose bounds differ from those of the original
9900 -- one, so we must ensure that a range check is performed.
9905 then
9909 -- Note: No Eval processing is required, because the prefix is of a
9910 -- record type, or protected type, and neither can possibly be static.
9912 -- If the record type is atomic, and the component is non-atomic, then
9913 -- this is worth a warning, since we have a situation where the access
9914 -- to the component may cause extra read/writes of the atomic array
9915 -- object, or partial word accesses, both of which may be unexpected.
9921 then
9922 Error_Msg_N
9925 Error_Msg_N
9933 -------------------
9934 -- Resolve_Shift --
9935 -------------------
9942 begin
9943 -- We do the resolution using the base type, because intermediate values
9944 -- in expressions always are of the base type, not a subtype of it.
9957 ---------------------------
9958 -- Resolve_Short_Circuit --
9959 ---------------------------
9966 begin
9967 -- Ensure all actions associated with the left operand (e.g.
9968 -- finalization of transient objects) are fully evaluated locally within
9969 -- an expression with actions. This is particularly helpful for coverage
9970 -- analysis. However this should not happen in generics or if option
9971 -- Minimize_Expression_With_Actions is set.
9974 declare
9976 begin
9984 -- Set Comes_From_Source on L to preserve warnings for unset
9985 -- reference.
9994 -- Check for issuing warning for always False assert/check, this happens
9995 -- when assertions are turned off, in which case the pragma Assert/Check
9996 -- was transformed into:
9998 -- if False and then <condition> then ...
10000 -- and we detect this pattern
10002 if Warn_On_Assertion_Failure
10009 then
10010 declare
10013 begin
10014 -- Special handling of Asssert pragma
10018 then
10019 declare
10021 Original_Node
10022 (Expression
10025 begin
10026 -- Don't warn if original condition is explicit False,
10027 -- since obviously the failure is expected in this case.
10031 then
10034 -- Issue warning. We do not want the deletion of the
10035 -- IF/AND-THEN to take this message with it. We achieve this
10036 -- by making sure that the expanded code points to the Sloc
10037 -- of the expression, not the original pragma.
10039 else
10040 -- Note: Use Error_Msg_F here rather than Error_Msg_N.
10041 -- The source location of the expression is not usually
10042 -- the best choice here. For example, it gets located on
10043 -- the last AND keyword in a chain of boolean expressiond
10044 -- AND'ed together. It is best to put the message on the
10045 -- first character of the assertion, which is the effect
10046 -- of the First_Node call here.
10048 Error_Msg_F
10050 Expression
10055 -- Similar processing for Check pragma
10059 then
10060 -- Don't want to warn if original condition is explicit False
10062 declare
10064 Original_Node
10065 (Expression
10067 begin
10070 then
10073 -- Post warning
10075 else
10076 -- Again use Error_Msg_F rather than Error_Msg_N, see
10077 -- comment above for an explanation of why we do this.
10079 Error_Msg_F
10081 Expression
10089 -- Continue with processing of short circuit
10098 -------------------
10099 -- Resolve_Slice --
10100 -------------------
10109 begin
10112 -- Use the context type to select the prefix that yields the correct
10113 -- array type.
10115 declare
10122 begin
10130 then
10138 else
10143 else
10154 else
10164 -- If the prefix is an access to an unconstrained array, we must use
10165 -- the actual subtype of the object to perform the index checks. The
10166 -- object denoted by the prefix is implicit in the node, so we build
10167 -- an explicit representation for it in order to compute the actual
10168 -- subtype.
10173 declare
10177 begin
10188 then
10191 -- If the name is a selected component that depends on discriminants,
10192 -- build an actual subtype for it. This can happen only when the name
10193 -- itself is overloaded; otherwise the actual subtype is created when
10194 -- the selected component is analyzed.
10197 and then Full_Analysis
10199 then
10200 declare
10203 begin
10208 -- Maybe this should just be "else", instead of checking for the
10209 -- specific case of slice??? This is needed for the case where the
10210 -- prefix is an Image attribute, which gets expanded to a slice, and so
10211 -- has a constrained subtype which we want to use for the slice range
10212 -- check applied below (the range check won't get done if the
10213 -- unconstrained subtype of the 'Image is used).
10219 -- Obtain the type of the array index
10223 else
10227 -- If name was overloaded, set slice type correctly now
10231 -- Handle the generation of a range check that compares the array index
10232 -- against the discrete_range. The check is not applied to internally
10233 -- built nodes associated with the expansion of dispatch tables. Check
10234 -- that Ada.Tags has already been loaded to avoid extra dependencies on
10235 -- the unit.
10237 if Tagged_Type_Expansion
10243 then
10246 -- The discrete_range is specified by a subtype indication. Create a
10247 -- shallow copy and inherit the type, parent and source location from
10248 -- the discrete_range. This ensures that the range check is inserted
10249 -- relative to the slice and that the runtime exception points to the
10250 -- proper construct.
10259 -- The discrete_range is a regular range. Resolve the bounds and remove
10260 -- their side effects.
10262 else
10279 -- Check bad use of type with predicates
10281 declare
10284 begin
10287 then
10289 else
10294 Bad_Predicated_Subtype_Use
10299 -- Otherwise here is where we check suspicious indexes
10310 ----------------------------
10311 -- Resolve_String_Literal --
10312 ----------------------------
10323 begin
10324 -- For a string appearing in a concatenation, defer creation of the
10325 -- string_literal_subtype until the end of the resolution of the
10326 -- concatenation, because the literal may be constant-folded away. This
10327 -- is a useful optimization for long concatenation expressions.
10329 -- If the string is an aggregate built for a single character (which
10330 -- happens in a non-static context) or a is null string to which special
10331 -- checks may apply, we build the subtype. Wide strings must also get a
10332 -- string subtype if they come from a one character aggregate. Strings
10333 -- generated by attributes might be static, but it is often hard to
10334 -- determine whether the enclosing context is static, so we generate
10335 -- subtypes for them as well, thus losing some rarer optimizations ???
10336 -- Same for strings that come from a static conversion.
10338 Need_Check :=
10347 -- If the resolving type is itself a string literal subtype, we can just
10348 -- reuse it, since there is no point in creating another.
10354 and then not Need_Check
10356 N_Attribute_Reference,
10357 N_Qualified_Expression,
10358 N_Type_Conversion)
10359 then
10362 -- Do not generate a string literal subtype for the default expression
10363 -- of a formal parameter in GNATprove mode. This is because the string
10364 -- subtype is associated with the freezing actions of the subprogram,
10365 -- however freezing is disabled in GNATprove mode and as a result the
10366 -- subtype is unavailable.
10368 elsif GNATprove_Mode
10370 then
10373 -- Otherwise we must create a string literal subtype. Note that the
10374 -- whole idea of string literal subtypes is simply to avoid the need
10375 -- for building a full fledged array subtype for each literal.
10377 else
10383 or else Need_Check
10384 then
10391 then
10397 -- The validity of a null string has been checked in the call to
10398 -- Eval_String_Literal.
10403 -- Always accept string literal with component type Any_Character, which
10404 -- occurs in error situations and in comparisons of literals, both of
10405 -- which should accept all literals.
10410 -- If the type is bit-packed, then we always transform the string
10411 -- literal into a full fledged aggregate.
10416 -- Deal with cases of Wide_Wide_String, Wide_String, and String
10418 else
10419 -- For Standard.Wide_Wide_String, or any other type whose component
10420 -- type is Standard.Wide_Wide_Character, we know that all the
10421 -- characters in the string must be acceptable, since the parser
10422 -- accepted the characters as valid character literals.
10427 -- For the case of Standard.String, or any other type whose component
10428 -- type is Standard.Character, we must make sure that there are no
10429 -- wide characters in the string, i.e. that it is entirely composed
10430 -- of characters in range of type Character.
10432 -- If the string literal is the result of a static concatenation, the
10433 -- test has already been performed on the components, and need not be
10434 -- repeated.
10438 then
10442 -- If we are out of range, post error. This is one of the
10443 -- very few places that we place the flag in the middle of
10444 -- a token, right under the offending wide character. Not
10445 -- quite clear if this is right wrt wide character encoding
10446 -- sequences, but it's only an error message.
10448 Error_Msg
10455 -- For the case of Standard.Wide_String, or any other type whose
10456 -- component type is Standard.Wide_Character, we must make sure that
10457 -- there are no wide characters in the string, i.e. that it is
10458 -- entirely composed of characters in range of type Wide_Character.
10460 -- If the string literal is the result of a static concatenation,
10461 -- the test has already been performed on the components, and need
10462 -- not be repeated.
10466 then
10470 -- If we are out of range, post error. This is one of the
10471 -- very few places that we place the flag in the middle of
10472 -- a token, right under the offending wide character.
10474 -- This is not quite right, because characters in general
10475 -- will take more than one character position ???
10477 Error_Msg
10484 -- If the root type is not a standard character, then we will convert
10485 -- the string into an aggregate and will let the aggregate code do
10486 -- the checking. Standard Wide_Wide_Character is also OK here.
10488 else
10492 -- See if the component type of the array corresponding to the string
10493 -- has compile time known bounds. If yes we can directly check
10494 -- whether the evaluation of the string will raise constraint error.
10495 -- Otherwise we need to transform the string literal into the
10496 -- corresponding character aggregate and let the aggregate code do
10497 -- the checking.
10501 -- Check for the case of full range, where we are definitely OK
10507 -- Here the range is not the complete base type range, so check
10509 declare
10517 begin
10520 then
10526 then
10527 Apply_Compile_Time_Constraint_Error
10529 CE_Range_Check_Failed,
10540 -- If we got here we meed to transform the string literal into the
10541 -- equivalent qualified positional array aggregate. This is rather
10542 -- heavy artillery for this situation, but it is hard work to avoid.
10544 declare
10549 begin
10550 -- Build the character literals, we give them source locations that
10551 -- correspond to the string positions, which is a bit tricky given
10552 -- the possible presence of wide character escape sequences.
10566 -- Should we have a call to Skip_Wide here ???
10568 -- ??? else
10569 -- Skip_Wide (P);
10577 Expression =>
10584 -----------------------------
10585 -- Resolve_Type_Conversion --
10586 -----------------------------
10598 -- Set to False to suppress cases where we want to suppress the test
10599 -- for redundancy to avoid possible false positives on this warning.
10601 begin
10602 if not Conv_OK
10604 then
10608 -- If the Operand Etype is Universal_Fixed, then the conversion is
10609 -- never redundant. We need this check because by the time we have
10610 -- finished the rather complex transformation, the conversion looks
10611 -- redundant when it is not.
10616 -- If the operand is marked as Any_Fixed, then special processing is
10617 -- required. This is also a case where we suppress the test for a
10618 -- redundant conversion, since most certainly it is not redundant.
10623 -- Mixed-mode operation involving a literal. Context must be a fixed
10624 -- type which is applied to the literal subsequently.
10632 or else
10634 then
10635 -- Return if expression is ambiguous
10640 -- If nothing else, the available fixed type is Duration
10642 else
10646 -- Resolve the real operand with largest available precision
10650 else
10656 -- If the operand is a literal (it could be a non-static and
10657 -- illegal exponentiation) check whether the use of Duration
10658 -- is potentially inaccurate.
10663 then
10664 Error_Msg_N
10667 Error_Msg_N
10674 then
10677 else
10686 -- In SPARK, a type conversion between array types should be restricted
10687 -- to types which have matching static bounds.
10689 -- Protect call to Matching_Static_Array_Bounds to avoid costly
10690 -- operation if not needed.
10697 then
10698 Check_SPARK_05_Restriction
10702 -- In formal mode, the operand of an ancestor type conversion must be an
10703 -- object (not an expression).
10711 then
10717 -- Note: we do the Eval_Type_Conversion call before applying the
10718 -- required checks for a subtype conversion. This is important, since
10719 -- both are prepared under certain circumstances to change the type
10720 -- conversion to a constraint error node, but in the case of
10721 -- Eval_Type_Conversion this may reflect an illegality in the static
10722 -- case, and we would miss the illegality (getting only a warning
10723 -- message), if we applied the type conversion checks first.
10727 -- Even when evaluation is not possible, we may be able to simplify the
10728 -- conversion or its expression. This needs to be done before applying
10729 -- checks, since otherwise the checks may use the original expression
10730 -- and defeat the simplifications. This is specifically the case for
10731 -- elimination of the floating-point Truncation attribute in
10732 -- float-to-int conversions.
10736 -- If after evaluation we still have a type conversion, then we may need
10737 -- to apply checks required for a subtype conversion.
10739 -- Skip these type conversion checks if universal fixed operands
10740 -- operands involved, since range checks are handled separately for
10741 -- these cases (in the appropriate Expand routines in unit Exp_Fixd).
10747 then
10751 -- Issue warning for conversion of simple object to its own type. We
10752 -- have to test the original nodes, since they may have been rewritten
10753 -- by various optimizations.
10757 -- Here we test for a redundant conversion if the warning mode is
10758 -- active (and was not locally reset), and we have a type conversion
10759 -- from source not appearing in a generic instance.
10761 if Test_Redundant
10764 and then not In_Instance
10765 then
10769 -- If the node is part of a larger expression, the Target_Type
10770 -- may not be the original type of the node if the context is a
10771 -- condition. Recover original type to see if conversion is needed.
10775 then
10779 -- If we have an entity name, then give the warning if the entity
10780 -- is the right type, or if it is a loop parameter covered by the
10781 -- original type (that's needed because loop parameters have an
10782 -- odd subtype coming from the bounds).
10785 and then
10787 or else
10791 -- If not an entity, then type of expression must match
10794 then
10795 -- One more check, do not give warning if the analyzed conversion
10796 -- has an expression with non-static bounds, and the bounds of the
10797 -- target are static. This avoids junk warnings in cases where the
10798 -- conversion is necessary to establish staticness, for example in
10799 -- a case statement.
10803 then
10806 -- Finally, if this type conversion occurs in a context requiring
10807 -- a prefix, and the expression is a qualified expression then the
10808 -- type conversion is not redundant, since a qualified expression
10809 -- is not a prefix, whereas a type conversion is. For example, "X
10810 -- := T'(Funx(...)).Y;" is illegal because a selected component
10811 -- requires a prefix, but a type conversion makes it legal: "X :=
10812 -- T(T'(Funx(...))).Y;"
10814 -- In Ada 2012, a qualified expression is a name, so this idiom is
10815 -- no longer needed, but we still suppress the warning because it
10816 -- seems unfriendly for warnings to pop up when you switch to the
10817 -- newer language version.
10821 N_Indexed_Component,
10822 N_Selected_Component,
10823 N_Slice,
10824 N_Explicit_Dereference)
10825 then
10828 -- Never warn on conversion to Long_Long_Integer'Base since
10829 -- that is most likely an artifact of the extended overflow
10830 -- checking and comes from complex expanded code.
10835 -- Here we give the redundant conversion warning. If it is an
10836 -- entity, give the name of the entity in the message. If not,
10837 -- just mention the expression.
10839 -- Shoudn't we test Warn_On_Redundant_Constructs here ???
10841 else
10844 Error_Msg_NE -- CODEFIX
10847 else
10848 Error_Msg_NE
10856 -- Ada 2005 (AI-251): Handle class-wide interface type conversions.
10857 -- No need to perform any interface conversion if the type of the
10858 -- expression coincides with the target type.
10861 and then Expander_Active
10863 then
10864 declare
10868 begin
10869 -- If the type of the operand is a limited view, use nonlimited
10870 -- view when available. If it is a class-wide type, recover the
10871 -- class-wide type of the nonlimited view.
10875 then
10891 -- Conversion from interface type
10895 -- Ada 2005 (AI-217): Handle entities from limited views
10899 Error_Msg_NE -- CODEFIX
10902 Error_Msg_N
10904 N);
10907 and then not
10910 then
10912 Error_Msg_NE -- CODEFIX
10915 Error_Msg_N
10917 N);
10919 else
10923 -- Conversion to interface type
10927 -- Handle subtypes
10934 or else Interface_Present_In_Ancestor
10937 then
10939 else
10942 Error_Msg_N
10950 -- Ada 2012: if target type has predicates, the result requires a
10951 -- predicate check. If the context is a call to another predicate
10952 -- check we must prevent infinite recursion.
10958 or else
10960 then
10963 else
10968 -- If at this stage we have a real to integer conversion, make sure
10969 -- that the Do_Range_Check flag is set, because such conversions in
10970 -- general need a range check. We only need this if expansion is off
10971 -- or we are in GNATProve mode.
10977 then
10981 -- Generating C code a type conversion of an access to constrained
10982 -- array type to access to unconstrained array type involves building
10983 -- a fat pointer which in general cannot be generated on the fly. We
10984 -- remove side effects in order to store the result of the conversion
10985 -- into a temporary.
10987 if Generate_C_Code
10994 then
10999 ----------------------
11000 -- Resolve_Unary_Op --
11001 ----------------------
11010 begin
11013 Check_SPARK_05_Restriction
11017 -- Deal with intrinsic unary operators
11023 then
11028 -- Deal with universal cases
11031 or else
11033 then
11040 -- Generate warning for expressions like abs (x mod 2)
11042 if Warn_On_Redundant_Constructs
11044 then
11048 Error_Msg_N -- CODEFIX
11053 -- Deal with reference generation
11060 -- Set overflow checking bit. Much cleverer code needed here eventually
11061 -- and perhaps the Resolve routines should be separated for the various
11062 -- arithmetic operations, since they will need different processing ???
11070 -- Generate warning for expressions like -5 mod 3 for integers. No need
11071 -- to worry in the floating-point case, since parens do not affect the
11072 -- result so there is no point in giving in a warning.
11074 declare
11083 begin
11084 if Warn_On_Questionable_Missing_Parens
11088 then
11091 -- We are looking for cases where the right operand is not
11092 -- parenthesized, and is a binary operator, multiply, divide, or
11093 -- mod. These are the cases where the grouping can affect results.
11097 then
11098 -- For mod, we always give the warning, since the value is
11099 -- affected by the parenthesization (e.g. (-5) mod 315 /=
11100 -- -(5 mod 315)). But for the other cases, the only concern is
11101 -- overflow, e.g. for the case of 8 big signed (-(2 * 64)
11102 -- overflows, but (-2) * 64 does not). So we try to give the
11103 -- message only when overflow is possible.
11107 then
11112 else
11118 else
11122 -- Note that the test below is deliberately excluding the
11123 -- largest negative number, since that is a potentially
11124 -- troublesome case (e.g. -2 * x, where the result is the
11125 -- largest negative integer has an overflow with 2 * x).
11132 -- For the multiplication case, the only case we have to worry
11133 -- about is when (-a)*b is exactly the largest negative number
11134 -- so that -(a*b) can cause overflow. This can only happen if
11135 -- a is a power of 2, and more generally if any operand is a
11136 -- constant that is not a power of 2, then the parentheses
11137 -- cannot affect whether overflow occurs. We only bother to
11138 -- test the left most operand
11140 -- Loop looking at left operands for one that has known value
11147 -- Operand value of 0 or 1 skips warning
11152 -- Otherwise check power of 2, if power of 2, warn, if
11153 -- anything else, skip warning.
11155 else
11159 else
11168 -- Keep looking at left operands
11173 -- For rem or "/" we can only have a problematic situation
11174 -- if the divisor has a value of minus one or one. Otherwise
11175 -- overflow is impossible (divisor > 1) or we have a case of
11176 -- division by zero in any case.
11181 then
11185 -- If we fall through warning should be issued
11187 -- Shouldn't we test Warn_On_Questionable_Missing_Parens ???
11189 Error_Msg_N
11196 ----------------------------------
11197 -- Resolve_Unchecked_Expression --
11198 ----------------------------------
11200 procedure Resolve_Unchecked_Expression
11203 is
11204 begin
11209 ---------------------------------------
11210 -- Resolve_Unchecked_Type_Conversion --
11211 ---------------------------------------
11213 procedure Resolve_Unchecked_Type_Conversion
11216 is
11222 begin
11223 -- Resolve operand using its own type
11227 -- In an inlined context, the unchecked conversion may be applied
11228 -- to a literal, in which case its type is the type of the context.
11229 -- (In other contexts conversions cannot apply to literals).
11231 if In_Inlined_Body
11235 then
11243 ------------------------------
11244 -- Rewrite_Operator_As_Call --
11245 ------------------------------
11252 begin
11259 New_N :=
11270 ------------------------------
11271 -- Rewrite_Renamed_Operator --
11272 ------------------------------
11274 procedure Rewrite_Renamed_Operator
11278 is
11283 begin
11284 -- Do not perform this transformation within a pre/postcondition,
11285 -- because the expression will be re-analyzed, and the transformation
11286 -- might affect the visibility of the operator, e.g. in an instance.
11287 -- Note that fully analyzed and expanded pre/postconditions appear as
11288 -- pragma Check equivalents.
11294 -- Rewrite the operator node using the real operator, not its renaming.
11295 -- Exclude user-defined intrinsic operations of the same name, which are
11296 -- treated separately and rewritten as calls.
11305 -- Indicate that both the original entity and its renaming are
11306 -- referenced at this point.
11317 -- If the context type is private, add the appropriate conversions so
11318 -- that the operator is applied to the full view. This is done in the
11319 -- routines that resolve intrinsic operators.
11323 when N_Op_Add | N_Op_Subtract | N_Op_Multiply | N_Op_Divide |
11324 N_Op_Expon | N_Op_Mod | N_Op_Rem =>
11337 -- Operator renames a user-defined operator of the same name. Use the
11338 -- original operator in the node, which is the one Gigi knows about.
11345 -----------------------
11346 -- Set_Slice_Subtype --
11347 -----------------------
11349 -- Build an implicit subtype declaration to represent the type delivered by
11350 -- the slice. This is an abbreviated version of an array subtype. We define
11351 -- an index subtype for the slice, using either the subtype name or the
11352 -- discrete range of the slice. To be consistent with index usage elsewhere
11353 -- we create a list header to hold the single index. This list is not
11354 -- otherwise attached to the syntax tree.
11365 begin
11371 else
11372 -- We force the evaluation of a range. This is definitely needed in
11373 -- the renamed case, and seems safer to do unconditionally. Note in
11374 -- any case that since we will create and insert an Itype referring
11375 -- to this range, we must make sure any side effect removal actions
11376 -- are inserted before the Itype definition.
11382 -- If the discrete range is given by a subtype indication, the
11383 -- type of the slice is the base of the subtype mark.
11386 declare
11388 begin
11397 -- Take a new copy of Drange (where bounds have been rewritten to
11398 -- reference side-effect-free names). Using a separate tree ensures
11399 -- that further expansion (e.g. while rewriting a slice assignment
11400 -- into a FOR loop) does not attempt to remove side effects on the
11401 -- bounds again (which would cause the bounds in the index subtype
11402 -- definition to refer to temporaries before they are defined) (the
11403 -- reason is that some names are considered side effect free here
11404 -- for the subtype, but not in the context of a loop iteration
11405 -- scheme).
11426 -- The Etype of the existing Slice node is reset to this slice subtype.
11427 -- Its bounds are obtained from its first index.
11431 -- For packed slice subtypes, freeze immediately (except in the case of
11432 -- being in a "spec expression" where we never freeze when we first see
11433 -- the expression).
11438 -- For all other cases insert an itype reference in the slice's actions
11439 -- so that the itype is frozen at the proper place in the tree (i.e. at
11440 -- the point where actions for the slice are analyzed). Note that this
11441 -- is different from freezing the itype immediately, which might be
11442 -- premature (e.g. if the slice is within a transient scope). This needs
11443 -- to be done only if expansion is enabled.
11450 --------------------------------
11451 -- Set_String_Literal_Subtype --
11452 --------------------------------
11460 begin
11472 -- The low bound is set from the low bound of the corresponding index
11473 -- type. Note that we do not store the high bound in the string literal
11474 -- subtype, but it can be deduced if necessary from the length and the
11475 -- low bound.
11480 -- If the lower bound is not static we create a range for the string
11481 -- literal, using the index type and the known length of the literal.
11482 -- The index type is not necessarily Positive, so the upper bound is
11483 -- computed as T'Val (T'Pos (Low_Bound) + L - 1).
11485 else
11486 declare
11492 Prefix =>
11496 Left_Opnd =>
11499 Prefix =>
11501 Expressions =>
11503 Right_Opnd =>
11512 begin
11514 Set_String_Literal_Low_Bound
11517 else
11518 -- If the index type is an enumeration type, build bounds
11519 -- expression with attributes.
11521 Set_String_Literal_Low_Bound
11525 Prefix =>
11532 -- Build bona fide subtype for the string, and wrap it in an
11533 -- unchecked conversion, because the backend expects the
11534 -- String_Literal_Subtype to have a static lower bound.
11536 Index_Subtype :=
11543 -- In the context, the Index_Type may already have a constraint,
11544 -- so use common base type on string subtype. The base type may
11545 -- be used when generating attributes of the string, for example
11546 -- in the context of a slice assignment.
11571 ------------------------------
11572 -- Simplify_Type_Conversion --
11573 ------------------------------
11576 begin
11578 declare
11583 begin
11584 -- Special processing if the conversion is the expression of a
11585 -- Rounding or Truncation attribute reference. In this case we
11586 -- replace:
11588 -- ityp (ftyp'Rounding (x)) or ityp (ftyp'Truncation (x))
11590 -- by
11592 -- ityp (x)
11594 -- with the Float_Truncate flag set to False or True respectively,
11595 -- which is more efficient.
11598 and then
11604 Name_Truncation)
11605 then
11606 declare
11609 begin
11619 -----------------------------
11620 -- Unique_Fixed_Point_Type --
11621 -----------------------------
11630 -- Give error messages for true ambiguity. Messages are posted on node
11631 -- N, and entities T1, T2 are the possible interpretations.
11633 -----------------------
11634 -- Fixed_Point_Error --
11635 -----------------------
11638 begin
11644 -- Start of processing for Unique_Fixed_Point_Type
11646 begin
11647 -- The operations on Duration are visible, so Duration is always a
11648 -- possible interpretation.
11652 -- Look for fixed-point types in enclosing scopes
11661 then
11663 Fixed_Point_Error;
11665 else
11676 -- Look for visible fixed type declarations in the context
11687 then
11689 Fixed_Point_Error;
11691 else
11704 Error_Msg_NE
11706 else
11707 Error_Msg_NE
11714 ----------------------
11715 -- Valid_Conversion --
11716 ----------------------
11718 function Valid_Conversion
11723 is
11728 function Conversion_Check
11731 -- Little routine to post Msg if Valid is False, returns Valid value
11734 -- If Report_Errs, then calls Errout.Error_Msg_N with its arguments
11736 procedure Conversion_Error_NE
11740 -- If Report_Errs, then calls Errout.Error_Msg_NE with its arguments
11742 function Valid_Tagged_Conversion
11745 -- Specifically test for validity of tagged conversions
11748 -- Check index and component conformance, and accessibility levels if
11749 -- the component types are anonymous access types (Ada 2005).
11751 ----------------------
11752 -- Conversion_Check --
11753 ----------------------
11755 function Conversion_Check
11758 is
11759 begin
11760 if not Valid
11762 -- A generic unit has already been analyzed and we have verified
11763 -- that a particular conversion is OK in that context. Since the
11764 -- instance is reanalyzed without relying on the relationships
11765 -- established during the analysis of the generic, it is possible
11766 -- to end up with inconsistent views of private types. Do not emit
11767 -- the error message in such cases. The rest of the machinery in
11768 -- Valid_Conversion still ensures the proper compatibility of
11769 -- target and operand types.
11771 and then not In_Instance
11772 then
11779 ------------------------
11780 -- Conversion_Error_N --
11781 ------------------------
11784 begin
11790 -------------------------
11791 -- Conversion_Error_NE --
11792 -------------------------
11794 procedure Conversion_Error_NE
11798 is
11799 begin
11805 ----------------------------
11806 -- Valid_Array_Conversion --
11807 ----------------------------
11810 is
11825 begin
11826 -- Error if wrong number of dimensions
11828 if
11830 then
11831 Conversion_Error_N
11835 -- Number of dimensions matches
11837 else
11838 -- Loop through indexes of the two arrays
11846 -- Error if index types are incompatible
11852 then
11853 Conversion_Error_N
11855 Operand);
11863 -- If component types have same base type, all set
11868 -- Here if base types of components are not the same. The only
11869 -- time this is allowed is if we have anonymous access types.
11871 -- The conversion of arrays of anonymous access types can lead
11872 -- to dangling pointers. AI-392 formalizes the accessibility
11873 -- checks that must be applied to such conversions to prevent
11874 -- out-of-scope references.
11876 elsif Ekind_In
11878 E_Anonymous_Access_Subprogram_Type)
11880 and then
11882 then
11885 then
11888 Conversion_Error_N
11898 -- Conversion not allowed because of accessibility levels
11900 else
11901 Conversion_Error_N
11907 else
11911 -- All other cases where component base types do not match
11913 else
11914 Conversion_Error_N
11916 Operand);
11920 -- Check that component subtypes statically match. For numeric
11921 -- types this means that both must be either constrained or
11922 -- unconstrained. For enumeration types the bounds must match.
11923 -- All of this is checked in Subtypes_Statically_Match.
11925 if not Subtypes_Statically_Match
11927 then
11928 Conversion_Error_N
11937 -----------------------------
11938 -- Valid_Tagged_Conversion --
11939 -----------------------------
11941 function Valid_Tagged_Conversion
11944 is
11945 begin
11946 -- Upward conversions are allowed (RM 4.6(22))
11950 then
11953 -- Downward conversion are allowed if the operand is class-wide
11954 -- (RM 4.6(23)).
11958 then
11963 then
11964 return
11968 -- Ada 2005 (AI-251): The conversion to/from interface types is
11969 -- always valid. The types involved may be class-wide (sub)types.
11973 then
11976 -- If the operand is a class-wide type obtained through a limited_
11977 -- with clause, and the context includes the nonlimited view, use
11978 -- it to determine whether the conversion is legal.
11984 then
11989 then
11992 else
11993 Conversion_Error_NE
12000 -- Start of processing for Valid_Conversion
12002 begin
12006 declare
12014 begin
12015 -- Remove procedure calls, which syntactically cannot appear in
12016 -- this context, but which cannot be removed by type checking,
12017 -- because the context does not impose a type.
12019 -- The node may be labelled overloaded, but still contain only one
12020 -- interpretation because others were discarded earlier. If this
12021 -- is the case, retain the single interpretation if legal.
12029 then
12030 -- More than one candidate interpretation is available
12038 -- When compiling for a system where Address is of a visible
12039 -- integer type, spurious ambiguities can be produced when
12040 -- arithmetic operations have a literal operand and return
12041 -- System.Address or a descendant of it. These ambiguities
12042 -- are usually resolved by the context, but for conversions
12043 -- there is no context type and the removal of the spurious
12044 -- operations must be done explicitly here.
12046 if not Address_Is_Private
12048 then
12073 Conversion_Error_N
12076 -- If the interpretation involves a standard operator, use
12077 -- the location of the type, which may be user-defined.
12081 else
12085 Conversion_Error_N -- CODEFIX
12090 else
12094 Conversion_Error_N -- CODEFIX
12106 -- Deal with conversion of integer type to address if the pragma
12107 -- Allow_Integer_Address is in effect. We convert the conversion to
12108 -- an unchecked conversion in this case and we are all done.
12116 -- If we are within a child unit, check whether the type of the
12117 -- expression has an ancestor in a parent unit, in which case it
12118 -- belongs to its derivation class even if the ancestor is private.
12119 -- See RM 7.3.1 (5.2/3).
12123 -- Numeric types
12127 -- A universal fixed expression can be converted to any numeric type
12132 -- Also no need to check when in an instance or inlined body, because
12133 -- the legality has been established when the template was analyzed.
12134 -- Furthermore, numeric conversions may occur where only a private
12135 -- view of the operand type is visible at the instantiation point.
12136 -- This results in a spurious error if we check that the operand type
12137 -- is a numeric type.
12139 -- Note: in a previous version of this unit, the following tests were
12140 -- applied only for generated code (Comes_From_Source set to False),
12141 -- but in fact the test is required for source code as well, since
12142 -- this situation can arise in source code.
12147 -- Otherwise we need the conversion check
12149 else
12150 return Conversion_Check
12152 or else
12158 -- Array types
12164 then
12165 Conversion_Error_N
12169 else
12173 -- Ada 2005 (AI-251): Internally generated conversions of access to
12174 -- interface types added to force the displacement of the pointer to
12175 -- reference the corresponding dispatch table.
12180 then
12183 -- Ada 2005 (AI-251): Anonymous access types where target references an
12184 -- interface type.
12188 E_Anonymous_Access_Type)
12190 then
12191 -- Check the static accessibility rule of 4.6(17). Note that the
12192 -- check is not enforced when within an instance body, since the
12193 -- RM requires such cases to be caught at run time.
12195 -- If the operand is a rewriting of an allocator no check is needed
12196 -- because there are no accessibility issues.
12204 then
12205 -- In an instance, this is a run-time check, but one we know
12206 -- will fail, so generate an appropriate warning. The raise
12207 -- will be generated by Expand_N_Type_Conversion.
12211 Conversion_Error_N
12213 Operand);
12216 else
12217 Conversion_Error_N
12219 Operand);
12223 -- Special accessibility checks are needed in the case of access
12224 -- discriminants declared for a limited type.
12228 then
12229 -- When the operand is a selected access discriminant the check
12230 -- needs to be made against the level of the object denoted by
12231 -- the prefix of the selected name (Object_Access_Level handles
12232 -- checking the prefix of the operand for this case).
12237 then
12238 -- In an instance, this is a run-time check, but one we know
12239 -- will fail, so generate an appropriate warning. The raise
12240 -- will be generated by Expand_N_Type_Conversion.
12244 Conversion_Error_N
12249 -- Real error if not in instance body
12251 else
12252 Conversion_Error_N
12259 -- The case of a reference to an access discriminant from
12260 -- within a limited type declaration (which will appear as
12261 -- a discriminal) is always illegal because the level of the
12262 -- discriminant is considered to be deeper than any (nameable)
12263 -- access type.
12267 and then
12270 then
12271 Conversion_Error_N
12273 Operand);
12281 -- General and anonymous access types
12284 E_Anonymous_Access_Type)
12285 and then
12286 Conversion_Check
12288 and then not
12290 E_Access_Protected_Subprogram_Type),
12292 then
12295 then
12296 Conversion_Error_N
12301 -- Check the static accessibility rule of 4.6(17). Note that the
12302 -- check is not enforced when within an instance body, since the RM
12303 -- requires such cases to be caught at run time.
12308 N_Object_Declaration
12309 then
12310 -- Ada 2012 (AI05-0149): Perform legality checking on implicit
12311 -- conversions from an anonymous access type to a named general
12312 -- access type. Such conversions are not allowed in the case of
12313 -- access parameters and stand-alone objects of an anonymous
12314 -- access type. The implicit conversion case is recognized by
12315 -- testing that Comes_From_Source is False and that it's been
12316 -- rewritten. The Comes_From_Source test isn't sufficient because
12317 -- nodes in inlined calls to predefined library routines can have
12318 -- Comes_From_Source set to False. (Is there a better way to test
12319 -- for implicit conversions???)
12326 then
12329 -- Implicit conversions aren't allowed for objects of an
12330 -- anonymous access type, since such objects have nonstatic
12331 -- levels in Ada 2012.
12334 N_Object_Declaration
12335 then
12336 Conversion_Error_N
12341 -- Implicit conversions aren't allowed for anonymous access
12342 -- parameters. The "not Is_Local_Anonymous_Access_Type" test
12343 -- is done to exclude anonymous access results.
12347 N_Function_Specification,
12348 N_Procedure_Specification)
12349 then
12350 Conversion_Error_N
12355 -- This is a case where there's an enclosing object whose
12356 -- to which the "statically deeper than" relationship does
12357 -- not apply (such as an access discriminant selected from
12358 -- a dereference of an access parameter).
12362 then
12363 Conversion_Error_N
12368 -- In other cases, the level of the operand's type must be
12369 -- statically less deep than that of the target type, else
12370 -- implicit conversion is disallowed (by RM12-8.6(27.1/3)).
12374 then
12375 Conversion_Error_N
12384 then
12385 -- In an instance, this is a run-time check, but one we know
12386 -- will fail, so generate an appropriate warning. The raise
12387 -- will be generated by Expand_N_Type_Conversion.
12391 Conversion_Error_N
12393 Operand);
12396 -- If not in an instance body, this is a real error
12398 else
12399 -- Avoid generation of spurious error message
12402 Conversion_Error_N
12404 Operand);
12410 -- Special accessibility checks are needed in the case of access
12411 -- discriminants declared for a limited type.
12415 then
12416 -- When the operand is a selected access discriminant the check
12417 -- needs to be made against the level of the object denoted by
12418 -- the prefix of the selected name (Object_Access_Level handles
12419 -- checking the prefix of the operand for this case).
12424 then
12425 -- In an instance, this is a run-time check, but one we know
12426 -- will fail, so generate an appropriate warning. The raise
12427 -- will be generated by Expand_N_Type_Conversion.
12431 Conversion_Error_N
12436 -- If not in an instance body, this is a real error
12438 else
12439 Conversion_Error_N
12446 -- The case of a reference to an access discriminant from
12447 -- within a limited type declaration (which will appear as
12448 -- a discriminal) is always illegal because the level of the
12449 -- discriminant is considered to be deeper than any (nameable)
12450 -- access type.
12453 and then
12456 then
12457 Conversion_Error_N
12459 Operand);
12465 -- In the presence of limited_with clauses we have to use nonlimited
12466 -- views, if available.
12470 -- Helper function to handle limited views
12472 --------------------------
12473 -- Full_Designated_Type --
12474 --------------------------
12479 begin
12480 -- Handle the limited view of a type
12484 then
12486 else
12491 -- Local Declarations
12499 -- Start of processing for Check_Limited
12501 begin
12505 else
12507 Conversion_Error_NE
12512 -- Ada 2005 AI-384: legality rule is symmetric in both
12513 -- designated types. The conversion is legal (with possible
12514 -- constraint check) if either designated type is
12515 -- unconstrained.
12518 or else
12520 and then
12523 then
12524 -- Special case, if Value_Size has been used to make the
12525 -- sizes different, the conversion is not allowed even
12526 -- though the subtypes statically match.
12531 then
12532 Conversion_Error_NE
12535 Conversion_Error_NE
12540 -- Normal case where conversion is allowed
12542 else
12546 else
12547 Error_Msg_NE
12555 -- Access to subprogram types. If the operand is an access parameter,
12556 -- the type has a deeper accessibility that any master, and cannot be
12557 -- assigned. We must make an exception if the conversion is part of an
12558 -- assignment and the target is the return object of an extended return
12559 -- statement, because in that case the accessibility check takes place
12560 -- after the return.
12564 -- Note: this test of Opnd_Type is there to prevent entering this
12565 -- branch in the case of a remote access to subprogram type, which
12566 -- is internally represented as an E_Record_Type.
12569 then
12573 and then
12577 then
12578 Conversion_Error_N
12580 Operand);
12581 Conversion_Error_N
12584 Operand);
12586 Error_Msg_NE
12591 -- Check that the designated types are subtype conformant
12597 -- Check the static accessibility rule of 4.6(20)
12601 then
12602 Conversion_Error_N
12604 Operand);
12606 -- Check that if the operand type is declared in a generic body,
12607 -- then the target type must be declared within that same body
12608 -- (enforces last sentence of 4.6(20)).
12611 declare
12617 begin
12624 Conversion_Error_N
12633 -- Remote access to subprogram types
12637 then
12638 -- It is valid to convert from one RAS type to another provided
12639 -- that their specification statically match.
12641 -- Note: at this point, remote access to subprogram types have been
12642 -- expanded to their E_Record_Type representation, and we need to
12643 -- go back to the original access type definition using the
12644 -- Corresponding_Remote_Type attribute in order to check that the
12645 -- designated profiles match.
12650 Check_Subtype_Conformant
12653 Old_Id =>
12655 Err_Loc =>
12656 N);
12659 -- If it was legal in the generic, it's legal in the instance
12664 -- If both are tagged types, check legality of view conversions
12667 and then
12669 then
12672 -- Types derived from the same root type are convertible
12677 -- In an instance or an inlined body, there may be inconsistent views of
12678 -- the same type, or of types derived from a common root.
12681 and then
12684 then
12687 -- Special check for common access type error case
12691 then
12693 Conversion_Error_NE -- CODEFIX
12697 -- Here we have a real conversion error
12699 else
12700 Conversion_Error_NE